 Hello and welcome to this session. In this session we will learn how to calculate medication dosages by applying ratio and proportion by national analysis or formula method. First of all let us discuss translating medication dosages by applying ratio and proportion. Now we can use ratio and proportion calculations for a variety of oral, intramuscular, subcutaneous and intravenous calculations. Now we will learn that ratio is a relationship in terms of size, amount or quantity of two or more things. These are pairs of numbers which are used to make comparisons between the numbers. We generally separate the two numbers in the ratio with a colon. Suppose we want to write the ratio of these two numbers that is 1 and 2. So the ratio of these two numbers can be written as 1 when we put a colon that represents a ratio and then 2 on infection that is 1 upon 2 and we say it as 1 to 2. Also we know that proportion is a relationship of one part to another on the whole with respect to size, amount or quantity. It is an equation with a ratio on each side of equal sign. For example, 2 is to 3 is equal to 4 is to 6 or 2 upon 3 is equal to 4 upon 6. Now let us discuss an example to see how we can use ratio and proportion for calculating medical dosages. Now the example says that doctors order is equal to 240 milligrams of a medication EO that is per orem which means taken only. Medication label says that one tablet is equal to 120 milligrams. Now how many tablets will you administer? Now let us start with its solution. Now let the number of tablets that should be administered is equal to X. Now doctors order is equal to 240 milligrams of a medication but orem this means X tablets is equal to 240 milligrams. Now medication label says that one tablet is equal to 120 milligrams. Now from this we get the ratio as X tablets is to 240 milligrams and from this relationship we get the ratio as one tablet is to 120 milligrams. Now we will equate these two ratios and we have this proportion as X tablets is to 240 milligrams is equal to one tablet is to 120 milligrams. This implies X tablets upon 240 milligrams is equal to one tablet upon 120 milligrams. Now the first multiplying we get X tablets is equal to 240 milligrams into one tablet upon 120 milligrams. Now we will cancel milligrams with milligrams and 120 into 2 is 240. So this is equal to two tablets. Therefore we get X is equal to two tablets. So the patient should be administered two tablets. So for solving this problem we have used the concept of ratio and proportion. From these two statements we have called two ratios when we equated these two ratios and here we have written this equation in such a way that tablets pass first when milligrams. Now this is very important it doesn't matter which unit comes first as long as we are in the same order on both sides of the equal sign and on simplifying this equation we get the required answer. Now let us discuss how to calculate medication dosages by applying dimensional analysis. Now dimensional analysis is the simplest method of calculating all dosages it systematically converts one unit of measurement to another by using a conversion factor it works for a wide variety of oral infant muscular, subcutaneous and intravenous calculations in order to calculate dosages using by dimensional analysis set up an equation which consists of starting factor one or more conversion factors and the answer unit. After writing this equation the final step is to pass around numbers using simple mathematics and multiplying the remaining numbers so dimensional analysis is a systematic mathematical process that results in consistent accuracy providing the equation is set up correctly. Now in dimensional analysis we simply multiply straight across on both sides of the horizontal line it's applicable and on the right there is no cross multiplication or algebra involved in this method of problem solving. Now let us discuss an example here doctors order says tetracycline syrup 240 milligrams medication label says tetracycline syrup 60 milligrams per milliliter how many milliliters should you administer? Now we will solve this problem using dimensional analysis method for this we have to find out three things first is starting factor second is conversion factor and third is the answer unit here the starting factor is the dosage in the doctors order that is 240 milligrams so starting factor is 240 milligrams now we won't have answer in milliliters so the answer unit is milliliters now we have to find the conversion factor for this let us see the medication label which says that tetracycline syrup 60 milligrams per milliliter that is 60 milligrams per 1 milliliter that is the number of milligrams that are contained in each milliliter of the syrup so 1 milliliter is equal to 60 milligrams now our starting factor is in milliliters and answer unit is in milliliters it means we won't have result in milliliters so the conversion factor will be a fraction in which milliliter is in milliliters and denominator is in milligrams so now from this relation we have got the conversion factor as 1 milliliter upon 60 milligrams now we set up an equation as starting factor into conversion factor is equal to answer unit so this implies starting factor that is 240 milligrams into conversion factor that is 1 milliliter upon 60 milligrams is equal to answer unit that is in milliliters now milligrams tensors for milligrams and 16 into 4 is 240 and 4 into 1 milliliter is equal to 4 milliliters so you should administer 4 milliliters of syrup to the patient so here we have calculated the medication dosage using dimensional analysis method so in this session we have learnt how to calculate medication dosages by applying ratio and proportion dimensional analysis or formula method and this completes our session hope you all have enjoyed this session