hi everyone Dr Windsor here Welcome to our first pharmacology lecture this lecture will focus on chapter one and cover the basics of pharmacology so after completing this lecture you should have a better understanding of some of the basic terms and abbreviations associated with pharmacology also you should be able to State sources of drugs and provide examples from each of those sources in addition you'll have the ability to list and describe several classes of drugs that are utilized in surgery during this lecture we're also going to take a closer look at medication orders drug Distribution Systems drug forms and routes of Drug Administration and if that wasn't enough I will explain the process of pharmacokinetics as well as discuss the various aspects of pharmacodynamics so it sounds like we have a lot to learn in this first chapter so let's go ahead and get started before we dive into the content of chapter one I want to ask you a question why is learning about pharmacology so important in the role of the surgical technologist go ahead and pause this lecture and take a minute and jot down anything that comes to mind okay so hopefully you paused you took some time to do some brainstorming were you able to come up with any reasons I prepared a list before I but before I tell you what's on my list I want to provide you with a couple of statistics did you know that more than seven thousand deaths each year are attributed to medication errors this accounts for approximately 10 percent of all deaths associated with medical errors I don't know about you guys but I was shocked and horrified to discover that a study conducted at Massachusetts General Hospital and published in October of 2015 discovered that medication errors occurred in over half of the surgical procedures that were performed there and one last tidbit of information before we get to my list and I think you know where I'm going with this Research indicates that there have been documented instances of surgical patients dying as the result of receiving an incorrect drug due to the drug containing basins and medication cups not being labeled so as the surgical tech we are instrumental absolutely instrumental in reducing medication errors that can occur in the surgical setting and most importantly death due to those errors we are the extra eyes and ears right so how do we do this well according to the association of surgical technology we should follow six General guidelines which include following the six rights of medication including handling and dispensing following sterile technique when medications are dispensed onto the sterile field handling medications in the operating room under the direct supervision and Orders of the surgeon assisting with the development of knowing and adhering to the surgery Department's policies and procedures that mandate who should be involved in administering and dispensing medications in the perioperative setting a couple more here participating in the review of those policies and procedures and lastly completing continuing education so that we can remain current in our knowledge of safe medication practices so we will dig deeper into each of these as we progress through the contents of this course but for now I just want you to understand the importance of your role in safe medication practices in the operating room you are an essential component in ensuring that your patient gets the right drug at the right time now and so now that we have a better understanding of why pharmacology is essential in the role of the surge check let's begin by reviewing some terms related to pharmacology so pharmacology is defined as the study of how chemicals and biological systems interact heparin chemical for example is a drug right it's a chemical that binds to something called antithrombin in the blood right in the cardiovascular system and what it does is it inactivates the clotting process and that thins or anticoagulates the blood so in the broadest sense the science of pharmacology includes toxicology which is a branch of science concerned with the nature of effects and detection of poisons it also includes food science Agriculture and lastly medicine so in the areas of Medicine new drugs are being developed almost every day and it's not a New Concept that change is a constant in medication and the branch of pharmacology is no exception so as surgical technologists we need to understand current medications and Trends but also develop the ability to incorporate new medications in our surgical practice as they come available so as I was putting this together I started thinking back to a time when I first um started working in the operating room and not too long after that dermabond which is a type of surgical skin glue um it did not exist and surprisingly uh surgeons look to us the surge tag on guidance regarding how to use it so we have this new Fang dangled thing called skin glue and the surgeons are just befuddled by it right so while the surgeons did receive training on the use of Derma Bond it was not consistent with their existing knowledge the use of something like skin glue was very foreign to surgeons I observed two major hurdles in surgeons using this new medication first was that they needed to apply Dharma bond in three light coats allowing for some time to dry between each coat surgeons don't think that they have time for this so they just want to slop it on and then it doesn't dry and it gets smeared everywhere the second thing was that they were adamant about applying the dermabond and covering it with a dressing they had always covered the wound with a dressing this was really foreign to them that putting on the Derma Bond meant that they didn't have to cover the wound with a dressing anymore and so as the St it was my responsibility to clearly understand how dermabond was used and to guide my surgeons accordingly to you know ensure that the patient would have the best outcome possible so to summarize an understanding of pharmacology Basics like the terms and abbreviations can help with comprehension of current science and integration of new information so let's review a couple of terms now the first is adverse effect an adverse effect is an undesired or potentially harmful side effect of a medication for an example an adverse side effect of Heparin is heavy bleeding or oozing from Cuts or wounds remember Heparin is an anticoagulant it thins the blood the second term I want to go over is bolus a bolus is defined as a dose of medication that is given rapidly typically through an IV so for example a person with diabetes a boluses would be a dose of insulin that would be given to handle the rise in the patient's blood glucose level right which is their blood sugar okay so two additional terms that we should know are contraindication and absorption so deeper into the lesson it will become clear how these terms apply but for now understand that a contraindication is a reason against giving someone a medication some of the most common reasons for not giving someone a medication in other words giving the medication would be contra indicated are things like sensitivity or allergy to the medication pregnancy lactation renal disease and hepatic disease now absorption is the process by which medications are taken into the body absorption is how the drug gets into the bloodstream and there are several methods of absorption which we're going to talk about in Greater detail later on so next uh we're gonna take some time to discuss the various drug sources now a drug source is where the drug originates and there are three major drug sources that we're going to cover in this lecture and they include natural chemical and bio technology so as mentioned previously drugs today come from three main sources natural chemical and biotechnology so we're going to talk about each of these in a bit more detail so take a look at this amazing chart that I made you uh to show you uh the three main natural sources so that would be plants minerals and animals and we're going to talk about each of those now plants are one of the natural drug sources and at one time they were probably um one of the only types of natural drug sources but they become less and less common in the surgical Arena however when we look at alternative medicine we will find a lot it has a lot to do with the use of plants okay so some examples of medications that come from plants atropine morphine and digitalis now morphine is a narcotic and it comes from the seeds of the Opium poppy all right whereas atropine uh that's a drug that reduces secretions and causes smooth muscle relaxation it comes from the roots of a plant called the belladonna plant and then lastly digitalis is from the leaves of a purple Fox Glove and it is used to treat problems such as arrhythmias and congestive heart failure so those are just three examples there's more of course let's talk a little bit about minerals minerals is another natural drug Source often used in pharmacological agents and two examples are Silvadene cream and antacids probably most of us have taken Tums or Rolaids or Mylanta or something of that sort so antacids such as uh oh let me back up sylvanian cream let me talk about that first contains silver salts and when we have patients that have Burns this Silvadene cream is what we typically put on those Burns and then antacids such as Tums and Mylanta they contain calcium and magnesium respectively so now a little bit about animals our third and last natural source of drugs and particularly hormones and some common sources include pigs which you will hear referred to as porcine cows which we refer to as bovine and horses we refer to that as equine so some common example hormones derived from pigs include insulin which is used to control blood glucose levels it has also been derived from cows as well another example um of a hormone that's derived from pigs is thrio globulin which is a thyroid hormone also thrombogen which is a topical hemostatic it helps to stop bleeding that is derived from cows so we refer to that as a bovine derivative and then Premarin Premarin is the hormone estrogen and that is derived from the horse so we refer to that as equine now if you take a look at table 1.1 in your textbook there are some other examples of plant-derived drugs that are relevant to the surgical practice so be sure to take a peek at that now that we have a better understanding of natural drug sources let's take a closer look at chemical sources so if natural sources are the first sources of drugs then chemical synthesis is definitely the second now chemical drugs fall into two categories and you can see them in green on the slide in front of you and they are synthetic and semi-synthetic now synthetic drugs such as pain relieving uh the pain relieving drug Demerol are created or synthesized in the lab and they do that by only using laboratory chemicals aspirin is a good example of a semi-synthetic drug it is derived from a natural substance called salicylic acid now to synthesize semi-synthetic drugs such as various antibiotics amoxicillin is a good example scientists will first extract the active substance from Penicillin mold and then they'll purify it and alter it using chemical processes a similar process is used to synthesize antibiotics that belong to the aminoglycoside group however the active substance found in the bacterial species streptomyces is extracted to create antibiotics such as Gentamicin and streptomyosin as well as a variety of other ones so next we're going to talk about biotechnology so as I mentioned biotechnology it's the third and last drug source biotechnology refers to the concepts of genetic engineering and something called recombinant DNA remember DNA is deoxyribonucleic acid it is the genetic material that is contained within cells um and so thanks to biotechnology we've been able to significantly improve treatment for a a variety of conditions now biotechnology is used to produce proteins from bacteria and previously these proteins were only available from animals using biotechnology here's what they do scientists will alter the DNA of a bacteria to produce the proteins that they need to make drugs so scientists have used cells such as E coli remember E coli lives in our digestive tract and what they do is they take a very very small microscopic piece of genetic code that tells the cell to make a certain protein so that is going to be inserted into the E coli bacteria area and that little piece of genetic code is going to get incorporated into the bacteria's DNA and then it is going to use that code to produce the proteins that we want it to produce and it can do it really quickly which is awesome so it starts producing the protein and that specific protein is then extracted and it goes through a purification process in the lab more recently though scientists have been using mammalian cells cells of mammals such as those of the Chinese hamster ovary they shorten that to Cho so those are becoming the primary cell of choice because they have a more stable gene expression bacteria have the tendency to replicate themselves so fast to that sometimes they make mistakes so less mistakes and higher volumes of the desired proteins so using biotechnology is really great because it can um create proteins without animals and it can avoid the adverse side effects of animal derived drugs so some of the drugs shown here like Humulin out to place growth hormone and hepatitis B vaccine are some of the drugs produced using biotechnology Humulin is human insulin and activates also called ultiplase is a thrombolytic so it is used to break up blood clots Nutri pin is uh a human growth hormone and then another example is thyrogen thyrogen is a thyroid stimulating hormone and then lastly we have our hepatitis B vaccine which is of particular interest to us right because we are required to get the Hep B series as as healthcare workers all right so a little side note here uh these drugs can only be administered via injection and this is because they are proteins and if we were to take them in a pill form or something that we had to swallow the proteins are going to be broken down and consumed in our stomach so um you know before we finish up our discussion about biotechnology let's take a little look at figure 1.3 which illustrates how biotechnology Works using E coli so in essence the E coli bacteria act as these little bitty protein-producing Factory so part A shows the DNA of the E coli and then scientists insert into the E coli's DNA a gene that's going to code for a certain desired Protein that's the part B and then in part C we see that final step where E coli incorporates the gene into its DNA and then it's going to start replicating itself all the while producing those proteins all right so now we have a better understanding of the three types of major drug sources let's move on to talk about drug classifications so as surgical technologists we need to be able to classify or group similar drugs why do you think this is well the truth is when we understand how drugs are classified we can group and understand new drugs more easily and as I mentioned new drugs are coming out all the time so let's revisit the aminoglycoside group of antibiotics and you will find this true with other groups of medications as well this is a little trick that I learned and I want to pass it on to you remember I said that the aminoglycoside group of antibiotics are semi-synthetic drugs and they're derived from the bacteria streptomyces they include drugs like Gentamicin Tobramycin amicasin plasomycin streptomycin neomyosin and paramycin so do you notice anything about their names at all did you hear the sin at the end of each one let me read them again Gentamicin Tobramycin streptomycin neomycin right so this is just one example of how we can group drugs together to remember and understand them more easily if you can connect the fact that the majority of these Amino glycoside uh antibiotics end with the letter c i n is going to help you significantly um especially when it comes to taking a test or your certification exam so on this slide you're going to see the four common drug classification categories and they are therapeutic action physiological action body system and chemical type and it's important to note that the drugs in each category they have similar uses so if you take a look at table 1.2 you'll see several categories of drugs listed under each classification type for example analgesic do you see it there it falls under the classification therapeutic action an analgesic is used to relieve pain that's its therapeutic Action Now cholinergic drugs on the other hand they elicit a physiological action so what do they do they activate the parasympathetic nervous system let's move on to cardiovascular agents right they focus on a specific body system right and then lastly let's look at barbituate find it there in the charts right under chemical type it's classified by its chemical type because it's derived from a chemical called barbature acid all right next we're going to dive a bit deeper into each of these drug classifications so a couple important side notes about drug subcategories when we classify drugs there is important things to remember interestingly subcategories are more useful than the broad categories why do you think this is well the reason is because subcategories give more information or Clues to the drugs use or purpose like cardiovascular agents that helps us out a lot right we're familiar with the cardiovascular system so the use of medical terms as side signposts when placing drugs in groups is really helpful so let's use the term anesthetic as an example the a n the an anesthetic means without an aesthetic means pertaining to sensation what about the term thrombolytic thrombo means clot and lytic means per uh means pertaining remember the IC means pertaining uh uh to the to the breakdown of something right so uh you know but just a word of caution here some drugs can belong in multiple categories a good example of that is Zantac Zantac is characterized as an antacid a histamine receptor antagonist and also a gastric agent similarly is our friend aspirin aspirin is classified as an analgesic because it relieves pain but it's also classified as a fever reducer or antipyretic and anti-inflammatory because it reduces inflammation so let's start by talking about therapeutic action drugs in more detail now therapeutic action drugs they do something for the patient they do something for the patient I already mentioned that analgesics relieve pain so what do analgesics do for the patient they relieve the patient's pain what about an anti-inflammatory what do they do for the patient right they reduce the patient's inflammation similarly thrombolytics break down clots and anti-pyretics reduce fever they're doing something for the patient so take another look at table 1.2 and make sure you familiarize yourself with the other therapeutic action drugs listed there that I didn't mention and drug classification is physiologic action drugs in this category do something in the body so ask yourself what does a histamine blocker do in the body for example histamine blockers block histamine production what about a vasoconstrictor what do they do in the body if we think about what we know regarding our use of medical technology Vaso means blood vessel and constrictor refers to a muscle that contracts or it could be referring to a snake anyways so a vasoconstrictor causes the smooth muscles in the wall of the blood vessels to constrict that's what it does in the body all right uh similarly H2 receptor antagonist remember an antagonist opposes something um uh and so in H2 receptor antagonist prevents or opposes the production of gastric acid so these are just a couple examples again um be sure that you familiarize yourself with the rest of them in table 1.2 so we're going to move on to the third drug classification which is affected body systems as its name suggests drugs in this category are going to affect a targeted organ or organs of a body system so ask yourself what organ or body system does the drug affect I already mentioned that cardiovascular agents affect the heart and circulatory system so what about dermatologic agents remember dermato means skin and Logie means the science or study of and I see ick means pertaining to so dermatologic means pertaining to the science or the study of the skin now cortisone cream is an example of a dermatologic agent what about a gastric agent while organ or body system does the drug effect if you thought stomach you are correct so great job there again these are just a few examples so make sure you check out the others that are listed in table 1.2 so here we are at the fourth and final drug classification which is chemical type drugs in this category are grouped because of what they are right what chemical compound is the drug derived from barbiturates as previously mentioned are chemical compounds derive from barbituric acid benzodiazepines are also sometimes referred to as benzos and they are a class of depressant drugs whose core chemical structure is the fusion of benzene and diazepine benzodiazepine it all makes sense now some examples of benzodiazepines are Valium versat and Ativan and a couple examples of barbiturates are pentathol and brevitol again take a peek at table 1.2 all right we're motoring through here we are on to um talk a little bit more about uh just how we classify and sub-categorize drugs so remember drugs can fall under more than one classification and um rentinidine or Zantac is a good example of that so therapeutically it's an antacid physiologically it's an H2 blocker remember that has to do with the production of gastric acid it blocks that um and as a body system it is a gastric agent so drugs can fall under more than one classification we also talked about aspirin and how aspirin has more than one classification okay uh so to further complicate matters there are more there are more variations remember let's review aspirin aspirin has more than one therapeutic action right so it has uh subcategories under one specific classification right not uh one subcategory under three classifications like Zantac so again aspirin uh it's therapeutic effects are antipyretic analgesic and anti-inflammatory drugs can also be grouped by how we obtain them so here we're talking about over-the-counter and prescription drugs and these two categories are considered legal classifications now over-the-counter drugs they don't require us to have a doctor's prescription and we can just go into the store and find it on the shelf and take it you know to the checkout counter and you know leave with our aspirin our ibuprofen or our Flonase or whatever the case may be however prescription drugs are prescribed by a doctor or licensed medical professional and they have to be purchased at the pharmacy uh in addition prescription drugs can only be used legally by the person that the drug was prescribed to legally right if we buy something over the counter we buy a box of Sudafed and I because I have the sniffles and then a week later my mom has the sniffles I can say oh hey I have some Sudafed you know here I'll give it to you I'm not supposed to do that with prescriptions doesn't mean that we don't do it but legally we're not supposed to it's good to remember that both are regulated by the Federal Drug Administration the FDA so we'll dive deeper into the details involving over-the-counter prescription drug legalities in chapter two so stay tuned for that in a future lecture surgical techs need to know all about drug classifications and subcategories and this information is critical in helping us to understand how to handle and use a drug as well as how the drug works so now we have a pretty good understanding of drug classifications and subcategories I want to talk about medication orders so surgical texts communicate about drugs through medication orders prescriptions are one type of medication order but they don't cover the drugs in surgery that we use in surgery a prescription is an order for a specific drug like we talked about go ahead and take a look at figure 1.4 in your text and you can see an example of a prescription I put a couple examples up here on the um on the upcoming slide as well you'll be able to see a couple examples but I'm sure all of us have received a prescription at one time or another so notice that a prescription has several components which include the date the name of the patient the name of the drug the dosage the route of administration the frequency or time of administration and the prescribers signature the government also dictates who can write prescriptions and this is determined on a state level so that means that this can vary from state to state other things that have to be on the prescription is the prescriber's name and address and telephone number and something called their Drug Enforcement Administration number or their d e a number and while the prescription usually lists the drugs trade name sometimes you might find the generic name listed there instead it's also common for prescribers to use symbols and abbreviations which are then interpreted by the pharmacist so be sure to also familiarize yourself with the abbreviations noted in table 1.3 so another thing is that many pharmacies now utilize computer database systems that provide printouts for patients regarding drug information such as its side effects precautions normal usage and um and storage so most prescriptions are ordered electronically these a days because there can be and have been a lot of difficulties when interpreting written orders if you've ever seen a doctor's handwriting you will know why I'm saying this so as previously mentioned written prescriptions have little or no use in surgery and in addition to that all drugs used in surgery are going to be ordered by a physician so you might be wondering what do we do in surgery when we need to use medication and that's what we're going to talk about next so in surgery medication orders are going to be one of several types which could include standing orders verbal orders immediate or Stat orders and as needed or PRN orders now a standing order or protocol you might hear it called is the first type of Hospital medication order and while hospitals at large may have standing orders that guide the user prophylactic antibiotics prior to surgery and the operating room our standard orders come from the preference card so stand by for an example of a preference card on the next slide but a preference card contains standing orders for a particular medication that's going to be used in a particular surgical procedure by a particular surgeon so the preference card is specific to surgeon and procedure so for example Dr vigil Dr vigil is a peripheral vascular surgeon his unique preference card for abdominal aortic aneurysm repair calls for 5 000 units of Heparin remember which is an anticoagulant and 1 000 mL of sodium chloride solution which is saline and he wants this used for topical irrigation as such all medications are going to be listed on the preference card and they should be ready on the back table as the standard part of the setup for that procedure now verbal orders are also going to be common in surgery and the surgeon uh might be doing a surgery and request a specific medication be administered from the sterile field so the nurse is going to give it to us and we are going to prepare it give it to the surgeon the surgeon is going to administer it or the surgeon might want the anesthesia care provider to give some sort of specific magic medication so let's say that Dr vigil might ask the anesthesia care provider to administer 5000 units of Heparin in the patient's IV he might also ask for gel foam and thrombin which is um a hemostat topical hemostatic agent to be delivered to the sterile field to help control excessive bleeding and those medications that are that live on the preference card those medications are standing orders every single case we're going to have those um and we're going to have them ready in case there's you know unless let's say the patient has an allergy or the surgeon comes in and specifically says he wants to use something else we're always going to have those ready these verbal orders are typically a one-time single administration of the medication so it's important to also note that all of the verbal orders for medications that are given during a surgery are going to be documented in the patient's chart so let's talk about stat orders and PRN orders now a stat order is a type of verbal order that indicates that the drug needs to be administered now immediately and commonly stat orders are given during emergency situations such as Cardiac Arrest now PRN stands for pro Ray NATA which is Latin for give as needed so this PRN means the drug should be given as needed for example let's say that the patient is having a breast biopsy and the breast biopsy is being performed under local anesthesia and the surgeon suspects that the patient might need help with pain control post-operatively he might order Demerol to be given PRN postoperatively to to manage the patient's pain so I hope that makes sense so here is a look at the preference card and the the medication orders for a surgery that are stated on the preference part they need to have at least three basic parts so if you look at that area that I circled in yellow that says medication um that's the area uh that we're focusing right now um and again the three there should be three basic pieces of information we need to know the drug name the strength of the drug and the volume how much are we going to have on our field so if you look at this preference card um you will see that it does provide the name strength and volume of the drug so it says the name is bupivacaine with epinephrine the strength is 0.5 percent and the volume is 10 MLS or milliliters so you can see some abbreviations there they use the W with the slash they used the ml um sometimes uh for Gage they'll put a g instead of gauge um I just want to draw your attention to this because you're going to see many abbreviations that represent drug forms and there's a table in your textbook it's table 1.5 it gives some of those abbreviations so take a peek at that and that's going to wrap up our discussion about medication orders so next we're going to talk about drug Distribution Systems foreign to say it's important to communicate about drugs properly but it's also important to distribute those drugs properly and different facilities have different ways of doing this um but this is the main tenet of drug distribution and like I said drug Distribution Systems vary but in surgery drugs are usually dispensed from one of three types of places which can include the hospital pharmacy some sort of or satellite Pharmacy or a type of medicine cabinet or cart now larger hospitals may have a satellite Pharmacy within the surgical department but smaller facilities may have a medication room or cabinet where they store frequently used medications other facilities May utilize mobile cart systems that are exchanged or need to be restocked at certain times of the day uh Crash Cart that's used during Cardiac Arrest uh is an example of this type of system lastly facilities may choose to use something called computer automated dispensing systems and these are a lot like vending machines but sadly they don't have Doritos or Hershey's bars in them but instead are filled with medications for distribution during surgery now these systems um have a variety of mechanisms that can help minimize medication administration errors which is really awesome it's important to also note that Controlled Substances like narcotics need to be stored in double locked locations uh typically there's one one person is designated to have the key or the code two people count the drugs at the beginning of the shift and similarly at the end of the shift I don't know if you guys have watched the good nurse but if you haven't maybe check out that movie it's pretty interesting it it has to do with these drug dispensing systems um so uh for my personal experience when I first started scrubbing the facility where I was hired used a medication box system so they were literally like these um tackle boxes these snack boxes um and they were stocked uh with commonly used meds and they were exchanged on an ad needed as needed bases with the pharmacy uh which means you know somebody would have to go down to the pharmacy and take the the box that was out of whatever and get a new one but later on the facility moved to the use of computer automated dispensing systems and we had one in each operating room it's called the Pixis and the machines were restocked at the end of the day but the machines had like a little computer screen and you had to have a code to get into it which the nurses on the on the um anesthesia care providers had the surgical techs did not have access to that um but you you know put your code into the screen and do you pull up whatever drug you want and how many and then a little drawer pops open with them in it and you know you get them out and you shut the drawer and so uh theoretically at the end of the day there should be that um you know inventory of the the machine started out with this many vials of Demerol and five were used and so this mini should be left and so it helps with um tracking of the medication as well um similarly narcotics that were used from the drug dispensing system need to be wasted if the whole amount of the drug is not used you can't just um you know throw it in the garbage can it needs to be quote unquote wasted which still should not be shot into the trash can that that's not a good practice but narcotics need to be wasted with another person um another experience I had was at a surgery center where I worked and we basically had these big they looked like um rolling tool boxes they were like red with the metal drawers that pulled open and they were stocked with the surgical drugs um and anybody and everybody could have access to them that was in the hall you know what had the lidocaine and you know um you know various things like that but narcotics were not stocked in those carts so some different examples um depending on the size of the facility they may you know have different um Distribution Systems that they use so after the second portion so that was the first portion of the lecture lecture uh we got through that so uh after the second portion we will be able to list and describe types of drug forms comparing contrast medication routes that we use in surgery explain the processes of pharmacokinetics and Identify and discuss the various aspects of pharmacodynamics it sounds so fun okay first off drug forms so a drug form is the Drug's appearance or how it is prepared now drugs uh do come in many different forms uh and preparations but can largely be grouped into four categories and these categories are solids semi-solids liquids and gases so first we're going to talk about the solid form and many drugs come prepared in this form I'm sure we've all taken a pill before that is a solid form of a drug a pill a capsule a tablet those kinds of things um uh these types of medications are not commonly used in the operating room we may use some drugs that come as a powder or need to be reconstituted such as dantrolene but for the most part our patients are out and they we really don't want them to sit up and take a pill with a drink of water we also think about you know the immediacy of the uh that we want the the drug to act quickly right and taking a pill by the mouth doesn't do that either so um like I said powders or freeze-dried medications come in solid form but then we usually add uh IV saline or something like that to them to reconstitute them back to their liquid form and dantrolene is a good example of one remember dantrolene is used to treat malignant hyperthermia so moving on to semi-solids semi-solid drugs include creams Foams gels and also ointments so creams consist of an active ingredient and they are water-based but ointments uh have an active ingredient and then they are oil or petroleum based and then gels gels are typically a little bit thicker than creams but they're still going to be a water-based and there are a lot of semi-solids that we use in surgery some common ones include KY Jelly which is a water-based lubricant lidocaine Dolly which is a water-based topical anesthetic Silvadene cream which I mentioned before is that burn cream estrogen cream which is the hormone cream that sometimes the surgeon will use when packing the vagina and and Neosporin which is an antibiotic ointment of course this is not an exhaustive list but um but some commonly used ones so the third drug form is liquid and there are three types and those include Solutions suspensions and emulsions so Solutions are mixtures of drug particles and those drug particles that they're referred to as the solute and then there is the liquid which is the solvent now Solutions have the solute it and it's fully dissolved in the liquid it completely mixes up you can't distinguish the um the solute from the solvent and an example of that would be saline or 0.9 sodium chloride and uh the saline solution is sodium chloride which is salt that's the solute and it is dissolved in water which is the solvent now suspensions are a little bit different they have solid particles floating in a liquid but the particles do not dissolve they're undissolved so uh the solid particles uh pretty much uh settle to the bottom of the liquid so these medications are going to need to be shaken prior to Administration so that those particles get evenly distributed throughout the liquid and an example of this medication is um one that we use in the ear it's called cordesporin otic or otic and this is used to treat infections of the ear and also to help reduce inflammation so it's Hydrocortisone and uh Neosporin together now uh quick question here how many of you have ever eaten mayonnaise mayonnaise is a common example of an Emulsion an emotion Emulsion is the third type of liquid that I want to talk about uh emulsions consist of uh not in the case of mayonnaise but in the case of medicine uh medication that is contained in a mixture of oil and water and held together with something called an emulsifier and an emulsifier simply serves to bind those two substances together have you ever tried to to mix oil and water it doesn't work right so an emulsifier would be the thing that binds uh in the case of mayonnaise I think it's eggs um but the most common Emulsion that we use in surgery is called far and it is the image that you see in this picture and I circled the proof on the label that this is in fact an Emulsion and propofol is uh you might have heard it referred to as the Michael Jackson drug but it is a sedative agent that's administered through the patient's IV by the anesthesia care provider in surgerys propofol is used for almost every single surgery that we do uh before I move on it's important to note that drugs in liquid form may be administered orally as something called elixirs or syrups so probably most of us have had cough syrup at some time or another syrups are sweetened aqueous Solutions Water Solutions and elixirs are sweetened Solutions of alcohol so uh elixirs and syrups uh but again due to the surgical patient's inability to receive medications through the mouth elixirs and syrups are not typically used in surgery okay uh our last form our drug form is gases they are the fourth and final drug form and really nitrous oxide is the only common medication that is available in gas form however we do use some inhalation anesthetic agents in surgery however and some are depicted in this picture that you see here on the slide but they don't start out as gases they are actually considered volatile liquids and what we do is we put these liquids into the anesthesia machine and it has a vaporizer and so the anesthesia machine is going to vaporize these volatile liquids into a gas form so that the patient can breathe it in all right so we are going to move forward to uh Administration routes now drugs have to get into the body to be able to work right and so the way that they get in is through an Administration route and drugs are designed with this in mind all right um and when they are that means that that drug can only be administered via that specific route so this means that they are not interchangeable if a medication is designed to be administered through injection like Zofran should be administered through injection drinking it is not a good idea all right it shouldn't be administered by uh any other route now two categories of medication administrated routes are in Terrell and parenteral enteral meaning through the gastrointestinal tract this can happen in one of two ways either orally or rectally now oral is going to be the most common way to administer medications but again it's very rare in the surgical setting for the reasons we have already discussed so you may see the oral route written as capital P capital o p o so this is an abbreviation for the Latin term per us per us which means by mouth all right so if something is po that means you take it by your mouth all right now medications giving orally take longer to take effect and the the time that elapses between taking a medication or the administration of a medication and when we see the effects of it in the body that time lapse is called the onset so when we take a pill it has a longer onset think about if you have a headache all right when you take ibuprofen Tylenol Advil something of that sort it's probably going to take 20 to 30 minutes before you start feeling some relief all right that is the onset however uh this uh it you know it typically when we take something by mouth um it has a longer onset so it takes longer for us to feel the effect but it's going to last longer in the body and how long the effect lasts in the body we call that the duration question so pills taking orally have a longer onset and a longer duration so to review in Terrell means through the GI tract however some medications are inactivated when they pass through the stomach so because of that um those medications need to be given parentally and parenteral refers to any route other than the digestive tract okay so some of the most common types of parenteral routes are topical subcutaneous intramuscular and intravenous and most medications administered in surgery are going to be administered parentally so we're going to spend some time talking about each of those routes in a detail so first up topical a topical medications are those that are applying to either the skin or to a mucous membrane-lined cavity and these medications have either a local effect or a systemic effect local meaning they work at the site of application wherever you put it on it just works right there an example of a topical medication that works at the site of application is steroid cream or maybe some anti antibiotic ointments topical medications that have a systemic effect mean that they're going to have an effect on the entire body and a good example of this at our transdermal patches that we stick on the skin such as those that are used for hormone replacement therapy for helping individuals to quit smoking or for motion sickness those are some good examples of topical medications that have a systemic effect on the body so it takes some time for topical medications to absorb through the skin however if we apply these topical medications to a blood supply Rich mucous membrane they're going to absorb much more quickly some common topical medications used in surgery are various antibiotic ointments topical hemostatic agents antibiotic irrigation and some topical arrogance such as Heparin mixed with saline so now that we have a better understanding of of [Music] um topical um medication let's talk about uh installation now examples of medications uh commonly used that are administered by installation include tetracaine eye drops or that are used to reduce pain during cataract removal Afrin form vasoconstriction in the nose prior to sinus surgery Lidocaine jelly in the urethra prior to a cystoscopy to reduce pain ah contrast media used in the biliary tract during a clangiogram and methylene blue in the uterus to determine tube patency so these medications are going to be inserted into mucous membrane-lined cavities again like the examples showed in the eye the nose the urethra those sort of things um then lastly the inhalation or route uh like it sounds uh uh Administration via inhalation indicates that these medications are going to be inhaled through the nose or the mouth and they can also um uh it's important to note that installation medications and inhalation medications can both be considered topical right so now that we have a better idea of some topical Administration routes or topical installation and inhalation routes let's talk about parenteral routes of administration so as I mentioned previously most drugs used in surgery are gonna be administered through the third and final Drug Administration route which is parenteral now parenteral routes include several types remember it's any route besides the GI tract so we're going to talk about the more common ones first which are subcutaneous which is abbreviated s c intramuscular which is abbreviated I am intravenous which is IV and IV injection so obvious uh the most common one used to administer medications in surgery is going to be IV injection and you can take a peek at figure 1.12 from the text and that will give you a better idea of these now subcutaneous injections are going to be those that are given just below the skin into the subcutaneous layer remember that's where a dermis and epidermis uh come together um common sides are upper lateral aspect of the arm the anterior thigh and the abdomen injections here depending on blood flow they're going to be absorbed fairly rapidly and in surgery we don't really use this route a lot except for in rare cases where they might inject Heparin subcutaneously but I've never witnessed that in my time working in the OR now intramuscular injections are going to be administered into a large muscle such as the deltoids the glutes or the vastus lateralis these medications are going to be absorbed very quickly via this route because there is a significant blood supply uh in the muscles so Toradol which is a non-steroidal anti-inflammatory drug it's sometimes given in surgery by the anesthesia care provider to provide post-op pain relief so Toradol would be an example of an intramuscular injection in surgery it's very important for the surgeon to inject local anesthetic at the surgery site so um later on uh you know several chapters in we will discuss local anesthetics in Greater detail but it is very common for us to have local anesthetic on the field that the surgeon is going to inject right at the surgical site um but like I mentioned before most medications are administered through the IV during surgery and this is typically going to be performed by the anesthesia care provider drugs uh they may be given as a bolus which is all at once or delivered slowly over time the absorption of medications administered IV are going to be absorbed immediately so they're going to have a really quick onset because they go directly into the bloodstream so I just want to talk about a few not so common parenteral routes so other parenteral routes um like the one shown here as I said are used less often they include intradermal intra-articular intrastical and intracardiac now intradermal injections they are the ones that are given between the layers of the skin and this is our TB test or allergy testing is done this way as well intra-articular medications are given in to the joint space an example would be some sort of anti-inflammatory agent sucks such as dexamethasone or something like that intraphical medications are those that are administered via a catheter that goes into the subarachnoid space and into the cerebral spinal fluid and an epidural is a common example of this one and then during cardiac resuscitation sometimes drugs such as epinephrine might be injected directly into the heart and this is referred to as intra cardiac injection so take a few minutes and reflect on what you've learned so far I know we've talked about lots of stuff and then list three of those things that you learned that you didn't already know all right so are you hanging in there with me I know this is a lot of information but we only have two more Concepts to discuss and those are pharmacokinetics and pharmaco Dynamics pharmacokinetics that is defined as the study of how the body processes drugs whereas pharmacodynamics examines how the action of a drug affects the body so pharmacokinetics how the body acts on the drug and pharmacodynamics how the drug acts on the body all right so first we're going to talk about pharmacokinetics and if you take a look at table 1.7 in the text you're going to see that there are four processes associated with pharmacokinetics and these are absorption distribution so let me back up absorption how is it going to get in distribution where is it gonna go bio transformation or also called metabolism how is it going to get broken down and then lastly excretion how does it leave all right so we're going to look at each of these in a bit more detail so as I mentioned pharmacokinetics involves absorption distribution biotransformation also called metabolism and excretion so think way back to chemistry class all right kinetics remember has to do with forces energy and motion so you can think of pharmacokinetics as the force or effect that the body has on a medication as it moves through the body so the first step in the process in pharmacokinetics is absorption so in absorption the drug is taken into the body and it's going to move away from the administration site and towards the bloodstream its goal is to get in the bloodstream now the administration routes that we discussed earlier those are going to determine which body systems are involved medications absorbed through the skin are gonna absorb a lot more slowly than those administered in the IV those administered in the IV like I said are going to absorb immediately and those absorb through the GI tract are gonna be somewhere in between those extremes right so on this slide you can see the process of absorption of the medication administered via the oral route uh it's also important to note that solubility makes a difference and the solubility of a drug is its ability to be dissolved so that's going to affect the absorption rate if the drug dissolves really fast it's going to be absorbed more quickly but if it dissolves really slow it's going to take a lot longer for the medication to be absorbed so certain factors are going to impact how quickly drugs are absorbed right uh before a drug can be absorbed again it has to be dissolved remember solubility equals dissolvability so Administration route blood supply to the area and Drug solubility are three major factors that impact absorption and if the vascular supply to the area is significant then it's going to absorb more quickly but if there's not a lot of vascular Supply then of course it's going to absorb a lot more slowly so oral absorption is also affected by a variety of factors remember the drug is going to have to pass through the digestive system and there are a lot of factors that can influence absorption and those are the pH uh if a patient has diarrhea then uh the medication is going to pass much more quickly through the system remember in the small intestine is where nutrients and molecules are absorbed so if the patient has diarrhea there's not going to be as much time for that medication to get absorbed and so not a lot of the patient's not going to get a lot of the medication conversely if a patient has constipation then the contents in in the intestine can be sitting in there for a really long time and that couldn't mean that too much of the drug gets absorbed and potentially the patient ends up with some sort of drug toxicity so the second process associated with pharmacokinetics is called distribution if you distribute something right you like pass it out right along and uh so uh after the drug is absorbed into the bloodstream the bloodstream is going to whisk it away and that means it's going to distribute it so this action again is carried out by the vascular system and once it enters circulation it's hopefully going to be on its way to the site of action now once it arrives at the site of action the drug is going to eventually leave the blood vessel all right it's going to diffuse out of the bloodstream it's going to move through that very thin wall of the capillary remember capillaries are all are uh so small that blood cells can only March through one by one right so and their walls are really really thin so the the molecules of the medication are eventually going to move out of those capillaries and into the interstitial spaces which are the spaces between the cells and eventually they're going to make their way into the cell right now when we talk about distribution we have to talk about bioavailability and this refers to the degree to which the drug molecule reaches the site of action to insert its effects so in other words it's how much drug is left to do the job once it reaches the site of action and there are a lot of factors that can influence bioavailability one of those is the acid base balance so when there is a change in pH level this can significantly and affect the bioavailability also the size of the drug if the molecules of the drug are really small it's going to be easier for them to pass through the plasma membrane remember their their goal is to get into the cell where they can you know elicit their their effect they can do their job a third thing that can influence bioavailability is something called lipid solubility so those molecules that are lipophilic which means they love their fat loving they're gonna pass more easily than those that are hydrophilic which means they're water loving remember think back to Anatomy when you study the cell now right the cell has what's called a phospholipid bilayer that's the plasma membrane right and the cell is surrounded with water outside and inside so if you have a molecule that loves water well it's really not even going to want to leave the interstitial space right because it loves just hanging out there um and also remember how the phospholipids arrange themselves in the plasma membrane they're water loving heads are to the outside and they're they're um hydrophobic tails are on the inside molecules that are lipophilic more easily pass through the membrane these are like like steroid uh steroids and uh hormones testosterone you know those kinds of um uh molecules that are fat loving they're just going to slip right through the plasma membrane now those that are hydrophilic they love water well they have to take a special pathway um and there's the specialized channels that will move those molecules right um so that can affect lipid solubility can impact bile of uh availability and then the last thing I have for you here is ionization of the drug molecule so those molecules that are non-ionized which means they don't have polarity they don't have a positive uh charge or a negative charge right that's going to mean they're going to be more swayed to like attract to someone that's the opposite right Opposites Attract pluses attract minuses it's going to be more difficult for them to pass through the membranes um if they are ionized okay so a few factors that impact how quickly the drug the drug reaches the action site now these are gonna include and this just makes sense to me the general condition of the patient's circulatory system the effect of blood flow to the site of action and the extent of something called plasma protein binding now this is abbreviated p p b and plasma protein binding involves the blood plasma and it has a major impact on drugs because drugs are carried by the blood in the blood right remember plasma is the liquid portion of blood and it contains these amazing proteins so just a quick review of blood structure remember blood is made up of formed elements and plasma the formed elements are cells so we have red blood cells white blood cells and thrombocytes you might have heard them called platelets and then the rest of it is the plasma and that is the liquid part of the blood and like I said it has a bunch of proteins in there now I'm telling you this because the proteins play a major role in how the drug um uh affects the binding site right so during the protein plasma protein binding all right some of the molecules bind to these proteins that are just floating around in the plasma the drug binding is going to be dependent on how many plasma proteins are there in the blood and something called drug binding Affinity all right some drugs have a very high affinity for binding to these plasma proteins While others could care less right so what happens we have these plasma proteins floating around in the blood and we have a drug that has a high affinity for binding to these proteins so what's going to happen is these molecules of the drug are going to bind to the proteins all right but not all of the molecules but let's say the majority of them right that means that there are going to be less molecules of the drug floating around freely in the plasma and these are the ones that are going to diffuse out and interact with the binding site so because uh when we have drugs that are called highly bound we're going to have a longer duration in the body because again there are less free drug molecules available to bind to the site of action and because of that highly bound drugs are going to stay in the body a lot longer so remember if a drug molecule is Unbound that means that it's free to go and bind to the side of action and then they have a special term for those free molecules that are Unbound we call them bioactive bioactive the ones that are Unbound they're not they don't have a seat at the table with the protein all right they're just Milling about so because plasma proteins can bind with many different drug molecules there's competition so plasma proteins they combine with many different types of drug molecules we refer to that as being unspecific so they don't care which drugs bind they're like meh we don't care everybody's welcome right so there's competition because that they don't care what molecules bind to them drug molecules also they compete with other drug molecules for binding sites okay which can change the amount of drug availability so let's talk about the example that the book gives the book gives the example of a patient that is lacking uh lacking not lacking taking taking Warfarin and Warfarin is a medication that thins the blood it is an anti-coagulant all right Warfarin is also considered a highly bound drug molecule remember this means that the majority of the drug molecules are going to bind to the proteins and then they're going to be very few free drug molecules to bind at the site of action at any given time so let's say the patient takes aspirin remember aspirin is also a blood thinner so aspirin is now going to be competing with Warfarin for those binding sites this means that there are going to be fewer seeds left at the table for Warfarin and consequently more free molecules of Warfarin are going to be wandering about and bioactive free to bind at the site of action so this can leave the patient dangerously anticoagulated right because they are getting a higher dose of Warfarin uh the uh and so the more than an expected amount of drug can lead to what we call over medication examples uh uh of a high of Highly bound drugs that we use in surgery are propofol which we already talked about Fentanyl and diazepam unfortunately the plasma protein binding process is a reversible and some ways that uh we can lower Unbound drug molecules is through metabolism or excretion which we're going to talk about uh coming up here but don't forget to take a peek at figure 1.14 which gives a good example of the plasma protein binding process okay so after distribution that was that whole distribution thing um there's going to be some Unbound drug remaining that did not get used up and eventually these Unbound drugs right they're traveling in the um cardiovascular system they're going to arrive at the liver the liver is the primary place where biotransformation takes place now biotransformation and Metabolism we use those to mean the same thing so I might say biotransformation I might say metabolism they mean the same thing so as the term biotransformation suggests this is the process that changes the drugs chemical composition and the main goal of the process is to change lipid-soluble drug molecules into water-soluble molecules so that they can be excreted more easily but there are some factors that can affect the metabolic rate and these include the health of the liver um and something called the first pass effect now the first pass a fact refers to when we take drugs orally now remember these drugs um they're gonna um they're gonna be subject to the hepatic portal system right this is like a safety mechanism so that whatever we ingested doesn't just go right into our bloodstream but gets filtered through our liver first so these drugs are going to enter the liver through the hepatic portal system prior to entering circulation and because of that they can be severely altered by that process or they can be inactivated altogether which is going to impact the Drug's effectiveness so how does the liver do this well the liver makes these amazing enzymes that help to break down drug molecules and the effectiveness of the liver enzymes to break down or metabolize the drug molecules depends on a bunch of factors those uh include the patient's age their nutritional status uh they're if they have any organ disease and any concurrent drug therapy that they're taking I was also reading an article that indicated that genetics can also be a factor there so it's important to note that Unbound drug molecules are the only drug molecules um available to exert effects on the body and those are the only ones that can be biotransformed so um there are some drugs that can be completely broken down by the liver other drugs aren't broken down at all but according to the text most drugs are at least partially broken down all right so uh one last thing here I think about biotransformation before we move on to excretion is something called Pro drugs and Pro drugs are inactive when they are administered but they go in going through the process of biotransformation they become switched on they become activated so an example of this is the anti-glaucoma drug called diphaver fern and this drug is administered in the eye and it's broken down at the site of administration through a process called hydrolysis and hydrolysis hydrolysis right uh the breaking down of something with water remember water carved in the Grand Canyon so uh it does have the power to break Bonds in molecules so the drug goes in the eye the water molecules in the eye react with the medication and the result is two entirely different molecules epinephrine and pavellic acid so uh This is Gonna wrap up our discussion on biotransformation and next we're going to learn about the last process of associated with pharmacokinetics which is excretion all right so drugs that are taken into the body right they're absorbed they're distributed they're metabolized and lastly they are excreted so some drugs are excreted in the bile or in feces some are actually excreted through the skin but the majority of them are excreted in the urine so take peek at finger 1.16 um for a a better idea of how excretion occurs but uh the what happens is the newly bio transformed drug is going to leave the liver remember that's the primary place for biotransformation or metabolization and so it's going to leave the liver via the bloodstream and it's going to go to the kidneys all right and it's going to be filtered out by the glomerulus remember that's the glomeruliar the filtration units of the kidneys we have bazillions of them right so they're going to go to work filtering out these um bioactive uh or biotransformed excuse me drug molecules so then tubular secretion uh is going to use cellular energy to force drugs and their metabolites from the bloodstream and they will become urine and get excreted from the body now something called the glomerular filtration rate which corresponds to not only how well your little filters in your kidney are working but perhaps how many you have because over time as we age we lose glomeruli but kidney disease can also impact that as well so uh renal failure pH of urine um and the concentration of drug molecules in the plasma can also be factors that impact the excretion rate so that's going to conclude our discussion about pharmacokinetics which is remember how the body processes the drug how the body acts on the drug so our final topic is going to be pharmacodynamics remember we said that pharmacodynamics is the study how of how drugs exert their effects on the body so here we're going to talk about what happens at the site of action and it's important to note that the body is going to respond to different drugs in varying degrees and at varying rates and sometimes varying from Individual to individual so next let's take a look at some terms associated with pharmacodynamics Agonist Agonist drugs are those drawings that have an affinity or they like they have a like for a receptor all right and they're going to cause a particular response when they bind with that receptor you can think of this like a lock and key situation there's a receptor the um the drug has an affinity for that receptor it fits it's the key that fits into the lock and it uh elicits a particular response an example of uh an Agonist drug is succinyl choline which is pretty common um you know anesthetic agent that they use but neurotransmitters like acetylcholine are also considered to be agonists they're lock and key which elicits a particular response now drugs that bind to receptors to inhibit a response those are called antagonists or receptor blockers now antagonists can be competitive which means they can bind to the sites where the agonists would bind preventing the agonists from binding there so that it can't elicit a response or non-competitive and non-competitive means that Agonist Alters The Binding site in some sort of way that makes it impossible for The Agonist to then bind there either way an antagonist is inhibiting a response now drug antagonism it's often responsible for what we call drug interactions and some of those are not desired interactions uh individuals that take multiple medications are at even higher risk of drug drug interactions and in some cases drugs can actually cancel each other out and then in other situations they can reduce the effects of another drug now let's talk about synergists synergists are drugs that enhance the effect of another drug so we talked about aspirin uh and Warfarin previously and this is an example of a synergistic relationship where aspirin is going to increase the effect of Warfarin right and then the result is that we have an over anticoagulated patient it's important to note that not all drug actions are receptor type interactions some actually interfere with certain aspects of bacterial cell metabolism metabolism like antibiotics will do that or others interact with specific enzymes uh in addition drugs such as manitol which is a diuretic is a non-specific interaction that reduces the rate absorption of water so this is going to increase urine output in our patient some other terms used to clarify aspects of pharmacodynamics include indication contraindication onset and duration the reason for giving a medication is going to be referred to as the indication the reason or purpose for giving a medication is the indication now the contraindication is going to be the opposite that's going to be the reason we wouldn't want to give a patient a particular drug and then the onset the onset is the time between the administration of the drug and the first sign of its effects which we talked about before and then lastly the duration the duration is the time between the onset and The Disappearance of the drugs effect and some drugs such as propofol they have a very short duration it's like six to eight minutes whereas other drugs such as morpherin it can be two to five days so if we have a patient that is taking Warfare in and they need to have surgery we may ask them to stop taking their Warfarin up to five days prior to their surgery a couple more here side effect adverse effect hypersensitivity and idiosyncratic drug reactions um side effect and adverse effect are used to describe the body's response or reaction to medication so side effects are rarely serious but are usually unavoidable they're also predictable but it's not something that we intended for the drug to do an example could be um after taking an antihistamine you might feel sleepy anniverse effect is one that is an undesired or potentially harmful effects and that could include things like nausea vomiting drug toxicity hypersensitivity and something called idiosyncratic which means like uh an idiosyncrasy is like we don't know like it was unusual it was not known it was something that we weren't aware of that could happen okay so we are at the end of our first lecture on pharmacology thank you so much for listening to this lecture regarding the basics of pharmacology I know it's a lot to take in it it might help it help to listen to the lecture more than once or maybe make flash cards of the various Concepts and terms so I will see you next time when we talk about medication development regulation and resources