hi my name is amanda and i'm a pharmacist today i'll be talking about days supply calculations and if you find this video useful please press the like button and subscribe to my channel and share it with others who may find it helpful too thanks i really appreciate it so first we'll just have an overview of day supply day supply is basically just how many days the quantity of a prescript prescribed medication will last like for example 7 days 30 days etc this video will cover day supply calculations for solid dosage forms this includes tablets and capsules oral liquids such as suspensions and solutions inhalers and nasal sprays eye and ear drops and injectables will be focusing on insulin so first we'll look at some basic information about the day's supply calculations day supply for a prescription may be given or it may need to be calculated if the day supply is given the amount of medication to dispense must be calculated this is done by taking the amount of medication used in one day and multiplying it by the number of days to use the medication so for example the prescription is for taking two tablets per day is for 30 days that would be 2 times 30 which would be to dispense 60 tablets if the day supply needs to be calculated you take the total amount of the medication dispensed and divide that by the amount of medication used in one day and in order to for this to work you these have to be in the same units and this is where the conversion calculations may be needed so for example if you have 60 tablets it's going to be the total amount of medication dispensed and the amount of medication used in one day was two tablets you would just divide 60 by two and that would give you 30 days so let's look more closely at the different types of prescriptions for the day supply first we'll start with the solid dosage forms and this includes tablets capsules suppositories or anything that's in a unit dose and i thought the best way to do this is to actually give prescription examples with a question so this first one is for metformin 500 milligram tablets one bid that's one twice a day dispense a one one-month supply refill times three so how many tablets should be dispensed for this prescription so we'll take our number of tablets used in one day multiply by the number of days that will give us the answer so one b id that would that's twice a day so that would be a total of two tablets in a day and times one month um one month a good number to use for that is just 30 days because that's a good round number so 2 times 30 will be 60 tablets we'll look at another example of solid solid dosage form day supply and this one is amoxicillin 500 milligram capsules 1tid uat means one three times a day until all are taken number 21 to be dispensed and no refills so here we have the quantity and we're going to need to calculate the day supply so what is the day supply for this prescription so we're going to take the total amount of medication dispensed divided by the amount of medication used in one day and that will give us the answer so the total is 21 capsules to dispense and one tid that's one three times a day so that would be a total of three capsules in a day so 21 divided by three gives us seven so it's a seven day supply now we'll look at the oral liquids day supply oral liquids this includes suspension solutions and syrups and this may involve the volume conversion calculations so i thought this would be a good place to review those the common volume conversion equivalents include one teaspoon equals five milliliters one tablespoon equals fifteen milliliters which equals three teaspoons one milliliter equals twenty drops which equals one cc one ounce equals thirty milliliters and 1 liter equals 1 000 milliliters so our first prescription we have here is for amoxicillin 250 milligram per 5 ml suspension and the directions are one teaspoon bid times 10 d that's one teaspoon full twice a day for 10 days dispense quantity sufficient qs and with no refills so how much amoxicillin suspension should be dispensed for this prescription from our conversion equivalents we know that one teaspoon equals five milliliters so this is for five milliliters one teaspoon bid which is twice a day so that would give us a total of 10 milliliters per day so now we're going to take the amount used in one day and multiply it by the number of days so that's 10 milliliters times 10 those 10 days gives us a total of 100 milliliters as well how much we need to dispense okay we'll look at one more example now for the oral liquid stay supply so we have robitussin ac cough syrup 1 teaspoon poq 4 to 6h prn cough that's one teaspoon full by mouth every four to six hours as needed for cough dispense four ounces with no refills so what is the day's supply for this prescription okay from our conversion equivalents we know that one teaspoon equals five milliliters so that's going to be five milliliters six times a day we get the six times a day because the maximum that could be taken would be it could be taken every four hours so there are 24 hours in a day so we would divide 24 by four which gives us six times a day so five milliliters times six times a day five times six gives us 30 milliliters that could be taken in one day and now we need to convert our amount dispensed also to milliliters because remember this has to be they have to be in the same units so we have 30 milliliters in one ounce and we're doing four ounces here so be 30 milliliters over 1 ounce times 4 ounces over 1 and our ounces cancel if you remember from our conversion calculations and so we have 30 times 4 gives us 120 milliliters so now we'll just take our total amount of medication dispensed and divide it by the amount of medication used in one day so 120 divided by 30 gives us a four day supply now we'll look at the inhalers and nasal sprays day supply so inhalers and nasal sprays have a specified number of metered doses per container the number of doses per inhaler or bottle of nasal spray is is product specific and can be found by reading the label on the product and the number of doses may be on the product label as metered inhalations this is usually for inhalers or metered sprays this will be for the nasal sprays or it may just say metered doses i'll look at our first example here albuterol inhaler 90 micrograms one to two puffs q6h prn wheezing dispens1 inhaler refill times three so that's we know from our albuterol package that it comes the one inhaler has 200 meter doses so if we calculate the maximum amount of medication for one day um the max would be two puffs and it'd be four times a day q6 hours you have 24 hours in a day divided by six hours will give us four times a day it could be used so 2 times 4 would give us 8 a maximum of 8 doses per day and we know from our package that it's 200 meter doses so now we'll just do our calculation of the total amount of medication dispensed divided by the amount of medication used in one day so we have 200 divided by 8 and that gives us a 25 day supply and one more example now with a nasal spray we have flonase nasal spray two sprays qd into each nostril dispense one bottle refill times two so qd is once a day so two sprays once a day and we know from our flonase bottle it has a 120 metered sprays in it so the amount of medication in one day two sprays into each nostril so you have two nostrils so be two times two that would be four and it's just once a day so it's a total of four sprays a day um so now we're gonna take the total amount of medication dispensed divided by the amount of medication used in one day so one bottle we know from the package it has 120 sprays we divide that by four sprays a day and that gives us a total of 30-day supply okay now we'll look at the eye and ear drops they supply day supply calculations for eye and ear drops they typically require a conversion calculation first and it's just the 1ml or milliliter equals 20 drops remember drops can be be abbreviated gtts so eye and ear drops come in different size bottles for example we can have a 2.5 milliliter 5 milliliter 10 milliliter bottle it's the same product but they just come in different sizes and sometimes a calculation is required to determine the correct bottle size to dispense to the patient with eye and ear drops so we'll look at that an example of that as well so our first eye and ear drop example we have a prescription for zalatan 0.005 ophthalmic solution and the directions are one gtt ou qpm that's one drop into each eye every evening dispense 2.5 milliliters with no refills so the question here is what is the day supply for this prescription so the directions are one drop into each eye every evening so that's just one drop and you have two eyes so that would be two drops and once a day so be two times one that gives us a total of two drops per day and we know from our conversion equivalent that one milliliter equals 20 drops so we simply take 2.5 milliliters and multiply it by 20 to find out how many drops are in the 2.5 milliliter package that gives us a total of 50 drops so now we're going to take our total amount of medication dispensed divided by the amount of medication used in one day so 50 drops is how much is to be dispensed divided by two drops 50 divided by two gives us a 25 day supply and one more example in the eye near drops and we have prednisolone one percent ophthalmic suspension two gtts os tid times 7d so that's two drops into the left eye three times a day times seven days dispense one bottle with no refills so what size bottle should be dispensed for this prescription and 2.5 5 or 10 ml sizes are available so those are our choices so this is for two drops three times a day just into one eye so it would be two times three that gives us a total of six drops per day and then we're gonna you do that for seven days so six drops a day times seven days six times seven is 42 drops total now we know from our conversion equivalents that 20 drops equals 1 milliliter so what we need to find out now is how many milliliters does 42 drops equal so we simply set up our conversion calculation 1 ml per 20 drops times 42 drops over one our drops cancel out we're left with milliliters and so we have 42 divided by 20 that gives us 2.1 milliliters so the size that would be closest to that would be the 2.5 milliliter bottle now we'll look at the injectables day supply we're really going to focus on insulin here because that's the most common day supply calculation for injectables and the doses for insulin are specified in number of units to inject and something to know about injectables is they may have a short expiration date after opening and this must be taken into consideration when determining the day supply for these products insulins expire 28 days after opening that's something you you'll want to know the number of units per milliliter in a valve insulin also depends on the specific insulin product a little more details about that u100 insulin is the most common concentration but there are others and with u 100 insulin that equals 100 units per milliliter and i've listed here some common u 100 insulin products um nova log or insulin aspart humalog which is insulin lispro lantis or basaglar which is insulin largene levomere which is insulin detemir and triceba which which is insulin deglodec so the the common insulins that are in the top 200 drugs are actually u-100 insulins but i have a note here that the traceba and the humalog are also available in u-200 so it's just something to watch for the concentration which is the units per ml of insulin is on the package if there are ever any questions you can just look at the package and see what the units per ml is on that and something that's helpful to know um a 10 milliliter valve of u100 insulin equals 1000 units so that's something you'll want to memorize so we'll look at a couple examples here atlantis 100 units per milliliter 5u sq qhs that's five units subcutaneously which is under the skin every night at bedtime dispense a 10 milliliter valve refill times three so what is the day's supply for this prescription so the amount for one day is 5 units because it's just 5 units once at bedtime and then a 10 ml val of u 100 insulin that's what we're dispensing here equals 1 000 units that's that little helpful thing i said to memorize um so we'll take the total amount of medication dispensed divide it by the amount of medication used in one day so we have a thousand units divided by five units so that equals a 200 day supply but insulin expires 28 days after opening so the day supply for this prescription would be 28 days one more example here for insulin and we have humolog quickpin u100 20u sqtid ac that's 20 units subcutaneously under the skin three times a day before meals and dispense five three milliliter pins and refill times two so what is the day supply for this prescription 20 units three times a day would be a total of sixty units for one day twenty times three and then to find out how much is in the the five pins we have three five three milliliter pins so that'll be a total of fifteen milliliters so we know this is u one hundred insulin so that means one hundred units per one ml and we'll multiply that by fifteen milliliters our milliliters cancel out we're left with our units on the top so that equals 100 times 15 equals 1500 units will be dispensed so now we're going to take our total amount of medication dispensed and divide it by the amount of medication used in one day so we have 1500 divided by 60 that gives us a 25 day supply we know insulin is good for 28 days so that day supply we can leave it as is so now we'll just look at a little summary of our day supply calculations um day supply is how many days the quantity of prescribed medication will last um if day supply is given the amount of medication to dispense has to be calculated and this is done by taking the amount of medication used in one day and multiplying it by the multiplying it by the number of days to use the medication and if day supply needs to be calculated we take the total amount of medication dispensed and divide it by the amount of medication used in one day and remember these must be in the same units for this to work and conversion calculations may be needed to obtain the same units before the day supply can be calculated so thanks for watching please like and share this video with others who may find it helpful and please subscribe to see more of my drug information videos thank you you