drug calculation formula

By rushing, you carry the risk of applying the incorrect divisor and undermining the end result. If the doctor orders 0.6 g, how much liquid will you give? CHAPTER 15 Dosage Calculation Using the Formula Method Objectives After reviewing this chapter, you should be able to: 1. From this, a formula can be adduced – a formula that can be used to calculate the amount of ingredient needed in a specific amount of product. from grams to kilograms and three places to the right every time you move down a unit e.g from grams to milligrams. Calculation stations are a crucial part of the MMI process - in this blog, we will show you how to approach questions for this particular station. When reducing formula – always double check you got the correct ratio. Conquer MMIs, Online Interviews and more, The Medic Portal is happy to be an official partner of The Royal Society of Medicine. Therefore you need to give a total dose of 50 mg. Many a times we have to calculate the drug doses based on the patient's weight. You need to give 50 mg and therefore need to find out what volume contains 50 mg. You can set up an equation where X is the volume of the solution you are trying to find: Some questions may give you a concentration in the form of a percentage, for example, a patient is given a 5% solution of a drug. Conversion from one unit of measure to another requires an additional calculation. You prescribe a patient 1 g of paracetamol. Drug calculations 1. Outlines Introduction Metric Conversions MG/KG Dose Conversion Flow Infusion Rates 3. This blog will take you through some of the more clinically useful calculations that could feature in these stations. Introduction When calculating how much of a drug is required, working with the formula helps the accuracy of the calculation. Explore all of our doctor-created interview prep in one place. Mon - Fri 9:00 to 17:00 GMT, Sign up to The Medic Portal for free application updates, The rationale for assessing calculation skills. Read on to learn what the drug dosage calculation formula is and how to use it. These will give you an idea of the level of difficulty you can expect. It is useful when the units of measurement are alike. You should practice these timed. %PDF-1.2 %���� Below, we review five examples of formulations and how best you should approach each problem. A pharmacist has been handed a prescription that asks for 200mL of chalk mixture, pediatric BP. How many mg are you giving the patient? This guide is not intended to be exhaustive, but the underlying principles remain the same. Whether you are allowed to use a calculator or not depends on the Medical School. 4. The multiplication difference here is 3 (300L divided by 100 parts – we now have a relationship between both: We need 15L of wood naphtha and 285L of spirit to produce 300L of (IMS) BP. 18 0 obj << /Linearized 1 /O 20 /H [ 1162 259 ] /L 39626 /E 33492 /N 3 /T 39148 >> endobj xref 18 38 0000000016 00000 n 0000001107 00000 n 0000001421 00000 n 0000001589 00000 n 0000001747 00000 n 0000001815 00000 n 0000002263 00000 n 0000002968 00000 n 0000003191 00000 n 0000003377 00000 n 0000003659 00000 n 0000003898 00000 n 0000004380 00000 n 0000004769 00000 n 0000011834 00000 n 0000012086 00000 n 0000012721 00000 n 0000021252 00000 n 0000021613 00000 n 0000022015 00000 n 0000023677 00000 n 0000023744 00000 n 0000029210 00000 n 0000029522 00000 n 0000029835 00000 n 0000029985 00000 n 0000030469 00000 n 0000030730 00000 n 0000031654 00000 n 0000031865 00000 n 0000032179 00000 n 0000032474 00000 n 0000032700 00000 n 0000032889 00000 n 0000033186 00000 n 0000033264 00000 n 0000001162 00000 n 0000001400 00000 n trailer << /Size 56 /Info 17 0 R /Root 19 0 R /Prev 39138 /ID[<098ae88ddf141691b977bd00af00d628><098ae88ddf141691b977bd00af00d628>] >> startxref 0 %%EOF 19 0 obj << /Type /Catalog /Pages 16 0 R >> endobj 54 0 obj << /S 51 /T 140 /Filter /FlateDecode /Length 55 0 R >> stream Consider the standard for industrial methylated spirits (IMS) BP – which states that ingredients should be in the ratio 95 parts spirit to 5 parts wood naphtha. Should I take BMAT in September or November? How Much Do You Know About Studying Abroad? Includes an online mock interview and an 85,000-word workbook, Our MMI Circuits have gone virtual! The decimal point moves three places to the left for every unit you move up (e.g. For example: You are asked to give a patient weighing 50 kg a 1 mg/kg IV injection. Some drug calculations may involve working out the volume of solution needed to give the required dose of a drug. As such, formulations form one of the many backbones of pharmacy calculations. Therefore we have introduced a maths test to ensure that students accepted to study medicine are able to undertake the type of calculation needed…”. How much of each ingredient is needed to produce 300L? Before you use the formula above, all units should be the same. You’ll find that formulations are quite straightforward, at least when compared to other topics in pharmaceutical calculations. Example calculations of dose based on BSA • A useful equation for the calculation of dose based on BSA is: • Patient’s dose = Patient’s BSA (m2) x Drug dose (mg) 1.73 m2 • If the adult dose of a drug is 100 mg, calculate the approximate dose for a child with a … By rushing, you carry the risk of applying the incorrect divisor and undermining the end result. By the same method, there is 3g of salicyclic and, by subtraction both values from 75g, there must be 92.5 grams of white soft paraffin. Alternatively, use the nursing formula: 400/2,000 x 1 = 0.2ml. Most likely, you will have time at the end of the exam to review your answers. You will also find out what the advantages are of adjusting the dose to the patient. One way to tackle these types of questions is to set up a simple equation where X is the variable you are trying to find. Identify the information from a calculation problem to place into the formula given 2. Calculate the number of tablets or capsules to administer 4. Keele also give more information about what you can expect during the test: “…the questions on the interview day will all be related to clinical scenarios, although no clinical knowledge is required to answer the questions..”, “…Simple calculators may be used and these will be supplied.”, “..TThe clinical maths test consists of 20 maths questions to be completed in 30 minutes. Formulations are by no means the most challenging topic in pharmacy calculations. It’s best, though, to secure the correct answer from the outset – approaching the question with a methodical, non-rushed approach that delivers the result you set out to achieve. Please enter username and password bellow! Since 2012, PharmaFactz has through our membership helped tens of thousands of In this case, the difference is 60 – that is to say, we need to create 60 times the listed formulation to make 600mL of medicine. Thus, convert 300 mg to g. 300 mg = 0.3 g The total amount of product is the sum of the parts of the ingredients. Which medicine course type would you suit? Most likely, you will have time at the end of the exam to review your answers. Formula Method This method is really a variation on the Ratio-Proportion Method. Nonetheless, if you are embarking on your pharmacy career as an undergraduate, you need to start somewhere. Call Us: +44 (0)20 8834 4579 Calculate the volume to administer for medications in… You may find it helpful to write out the number with a decimal point after it. You will be asked to undertake simple mathematical calculations involving data that has clinical relevance.”. Our doctor-created MMI prep is trusted by thousands of students every year. Find the quantity of ingredients needed to produce 50g of product using the following formula: The total ointment itself contains 40 parts. As a result, we must divide each ingredient in the formula by 5 – meaning the formula is now prepared to 200mL rather than 1,000mL. Those who qualify for the UCAT special educational needs [UCATSEN] test will be given extra time on the day. The rationale for assessing calculation skills according to Keele is as follows: “It is very important that doctors are able to use simple maths to solve problems during their work. How well do you know your medical history. There are no trick questions and the answers are all realistic.”. First, we need to add the parts – (95 + 5 = 100) – and relate this to the 300L required. By convention, this means there are 5 g of the drug in every 100 mL. In clinical practice one of the most useful type calculations to know how to perform is converting between units. Some drug calculations may involve working out the volume of solution needed to give the required dose of a drug. When taking a pharmacy calculation exam, always take your time. For example: By modifying the proposed recipe, we can create medicines of different amounts and volumes. The syringe contains 100 mg in 2 ml. students – all of whom vouch for the high-quality learning materials. Resultantly you are administering 10mg of lidocaine to the patient. Water to 10mL becomes water to 600mL of medicine. You could try to keep in mind the above when doing calculation. The percentage of ingredients can be used to produce a formula and, from there, the ingredients in a known amount of product can be calculated. Get doctor-designed strategies, delivered by top Medical School Interview Tutors. A: 5% means there are 5 g of WondaDrug in every 100 mL. With our text, you will also learn more about the various different kinds of dosing which you may encounter when using different medications. Calculating dose from mg/ kg body weight These calculations are mainly used for children, who need just… You need to move the decimal point six places if you move through two units (e.g from milligrams to nanograms). Once we understand how many parts there are what the final ingredient total needs to be, it becomes a matter of basic multiplication. Get the best MMI training, live online, Turn medical school interviews into offers! A formula can be expressed as a percentage – commonly seen in ointments and creams, for example. Keele have also released a document with some practice questions with complete worked answers. 1 x 50 mg = 50 mg. How much do you know about medical ethics? Calculate medication dosages using the formula DH×Q=x 3. This particular calculation would be considered to be a high-risk calculation because it has multiple stages in which errors can be introduced, and because of the small dosage involved and the conversion required between different units of measurement (NPSA, 2009b). 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The formula is listed as follows: The recipe we have prepares for 1,000mL, but the prescription asks for 200mL.