Dosage and Calculations Math

Common Conversions: 1 Liter = 1000 Milliliters 1L = 1000 mL 1 Gram = 1000 Milligrams 1g = 1000 mg 1 Milligram = 1000 Micrograms 1 mg = 1000mcg 1 Kilogram = 2.2 Pounds 1 kg = 2.2 lbs Methods of Calculation Any of the following three methods can be used to perform drug calculations. Please review all three methods and select the one that works for you. It is important to practice the method that you prefer to become proficient in calculating drug dosages. Remember: Before doing the calculation, convert units of measurement to one system. I. Basic Formula: Frequently used to calculate drug dosages. D (Desired dose) H (Dose on hand) V (Vehicle-tablet or liquid) D H x V = Amount to Give D = dose ordered or desired dose H = dose on container label or dose on hand V = form and amount in which drug comes (tablet, capsule, liquid) Example: Order-Dilantin 50 mg po TID Drug available-Dilantin 125 mg/5ml D=50 mg H=125 mg V=5 ml 50 mg 125 mg x 5 mL = 250 125 = 2 ml