Transcript for:
Understanding Aminoglycosides: Uses and Effects

hey everyone it's Sarah with registered nurse rn.com and in this video I'm going to be covering Amino glycosides so let's get started aminoglycosides are a particular group of antibiotics that Target mainly gram-negative microorganisms therefore they're really gram-negative Killers because they have this bacterial subtle effect on the bacteria where they go in and just kill it rather than just inhibiting its growth which would be known as having a bacteriostatic effect now as I cover the different types of antibiotics in this series you're going to see that some antibiotics are really good at killing bacteria whereas other types just really inhibit their growth so what gram-negative bacteria do aminoglycosides Target well they target E coli klebsiella pneumonia a pseudomonas ergonosa serratia marcessins and interobacter now they're not really helpful with targeting grandpas and microorganisms but they can kill a few such as staphylococcus aureus and then enterococcus furthermore aminoglycosides can Target mycobacteria infections such as mycobacterium tuberculosis so because of all these microorganisms that aminoglycosides can Target they're really good at treating certain cases of septicemia where we have infection in the blood severe cases of urinary tract infection and then infections that affect certain parts of the body such as the eyes the ears the bone the abdomen the pelvic areas and they can treat cases of endocarditis where you have infection in the heart specifically on those heart valves and then severe cases of pneumonia that are usually acquired from the hospital setting because those strains tend to be very severe now in practice you may see that aminoglycosides are used in combination with other types of antibiotics and the reason for this is because whenever you throw an aminoglycoside on let's say with Penicillin it all of a sudden has a synergistic effect which means it allows that aminoglycoside to work in ways where it normally wouldn't be able to work if it wasn't on board with this other type of medication so let's say we have Penicillin and aminoglycoside on well aminoglycoside without penicillin normally wouldn't be able to get inside that cell wall and kill it but because we have Penicillin on board we have the synergistic effect and aminoglycoside is able to get in and Target that bacteria so how do we remember the medications that are included with the aminoglycosides well let's remember the word Nats g-n-a-t-s so the GN part is going to help you remember that aminoglycosides mainly Target gram-negative microorganisms so the G is for Gentamicin n is for neomycin A is for Emma Cason T is for Tobramycin and then the last one s is for streptomycin now as you can see these medications in in mycin whether m-i-c-i-n or m-y-c-i-n but don't let that tip you off that it's an aminoglycoside because some other groups of antibiotics such as the microlides they end in nycin some of them do like erythromycin so that might throw you off and get you a little confused so just try to remember the names with this mnemonic and just know that unfortunately it doesn't follow that rule that sometimes we can use with those names now how are aminoglycosides administered well this particular group of medications doesn't like to be absorbed through the gut so we don't like to give them orally but rather we like to give them via the parental route so the im or IV route now there are some exceptions to this depending on what's going on with the patient for instance to cobramycin can be given via inhalation to patients who have cystic fibrosis and they have a lung infection or we can give neomycin via the oral route if we're trying to Target certain bacteria in the gut for instance if the patient has hepatic encephalopathy we can give them neomycin to help bring down that ammonia level or let's say the patient's having bowel surgery we can give them this to help prep that bowel before they actually have surgery so now let's talk about how aminoglycosides work and how they actually kill that bacteria well depending on the antibiotic group you're talking about they will Target certain parts of that bacterial cell some will inhibit the cell wall synthesis of that bacteria While others will inhibit nucleic acid synthesis and then some will inhibit protein synthesis within that bacterial cell and that is what aminoglycosides do they inhibit protein synthesis inside that bacterial cell so we don't get the creation of proteins now now proteins are really important for that bacterial survival it's really the backbone of its ability to thrive and survive so if we can stop that process of that bacteria that's inhabited our body we can kill it and get rid of it and that's what aminoglycosides do so what makes the proteins in that bacteria cell it is the ribosome so remember ribosome it's it's what we're targeting so the ribosome is a really cool structure it is made up of two subunits you have a large subunit known as 50s and then you have a smaller one known as 30s and these two subunits work together to their whole goal is to stack amino acids together and make a beautiful polypeptide chain hence our protein so aminoglycosides say I need to stop this process so I'm going to affect one of these subunits so we can't have this happen making these polypeptide chains so what it does is aminoglycosides binds to the 30s on the ribosome so it binds to the subunit particularly it's a site so remember aminoglycoside starts with a it targets the a site of 30s and whenever it does this it causes its genetic code to not be read properly so we don't have good instructions happening here so we're not going to really make great healthy proteins instead we're going to make junky proteins and junkie proteins lead to the death of that bacteria can't function if it doesn't have healthy ones so there we get that bacterial subtle effect and that is how in the end they kill the bacteria now let's talk about our role as the nurse whenever we're administering aminoglycosides so before administer during these medications you want to confirm that your patient is not allergic to them and that you've obtained any necessary cultures that have been ordered by The Physician and that you are monitoring the peak and trough levels why your patient is taking this group of antibiotics and the reason for this is because these medications are very powerful so we want to make sure our patient's not becoming too toxic on them because it has a very narrow therapeutic index but we want to make sure that the medications being effective and that they have enough of the medication in their system to really Target that bacteria and kill it so first let's talk about Peak so the peak is the highest concentration of the medication in the blood so remember this medication can be given I am or IV so if your patient's getting an IM you would want to do a blood draw for the peak one hour after the injection but let's say your patient is getting it IV it's typically a 30 minute infusion so you would want to do a blood draw about 30 minutes after the infusion has been completed and then the trough is the lowest concentration of the medication in the patient's system and we're really interested in this level because it helps us monitor for toxicity so if your patient's getting an IM or IV you would just collect it you do a blood draw right before the next dose and then another thing you want to be monitoring for is that this medication is working like it should so is the medication treating this infection what are some signs that tells you it's doing that well the patient doesn't have a fever anymore those fevers are dropping or they just don't have one anymore they're normal they don't show signs and symptoms of sepsis so their blood pressure is within normal range it's not hypotensive and their heart rates within normal range is not tachycardic and their white blood count is in normal range like five thousand to ten thousand anything greater than that tells us oh the white blood cells are on board we've got a massive infection because that's what white blood cells do they target bacteria so if they're elevated that's not a good thing now let's talk about the toxic effects that aminoglycosides can have in your patient that you want to monitor for so two terms I want you to remember nephrotoxic and ototoxic so in an O So in aminoglycosides remember the n and the O for nephrotoxic and ototoxic so nephro toxic in medical terminology remember nephro meant kidneys so we're talking about the kidneys the kidneys can really be affected and if they're affected it could be reversed so we can reverse the nephrotoxicity and what happens what increases the patient's risk of having this is that they've been using aminoglycosides for too long or they're on a really high dose so as a nurse when you want to be looking out for is you want to be looking at the patient's urinary output make sure that they're putting out a normal amount of urine so typically that's 30 ml per hour for an adult and you want to be looking at those labs that tells you about the renal function these will be ordered so you want to look those over like for instance the bun you want to make sure that's within normal limits like 5 to 20. and they're creating level anywhere between 0.6 to 1.2 milligrams per deciliter it varies depending on male and female and then you want to look at their GFR that is a glomerular filtration rate and this is the rate that our glomerulus filters waste ions and water so anything less than 90 ml per minute is concerning so we want to make sure that it doesn't get there now the next type of toxic your patient can experience is ototoxicity and Odo remember means ears and we're specifically talking about those hearing structures in the ear now if your patient experiences this unfortunately it's not likely going to be reversed like over here with the kidneys and what increases your patient's risk of developing this is if they're taking other medications that can really cause this to happen for instance if they're taking Loop Diuretics like furosemide it increases the risk of them developing hearing problems so because this medication can damage the vestibular and cochlear parts of the ears you want to tell your patient to Monitor and to report any type of ringing in the ear hearing loss or feeling dizzy because this could be a sign that this medication is messing with the ears and then lastly this medication can cause a neuromuscular blockade so this can be experienced through muscle weakness and respiratory failure and it tends to happen in patients who've received neuromuscular blocking medications like during anesthesia or who have neuromuscular disorders like myasthenia gravis so in these patients you want to make sure that you're on high alert for these potential problems like muscle weakness and respiratory failure that could develop while taking this medication okay so that wraps up this review over aminoglycosides and if you'd like to watch more review lectures over antibiotics in this series you can access the link in the YouTube description below