Unit 3 Lesson 3.2.4 Calculating Medication Dosages
Liquid and Weight Conversion Formula
Desired Dose over Dosage on Hand Times Vehicle over One = Dosage to be Administered
(Desired dose divided by Dosage on Hand x Vehicle divided by 1 = Dosage Administered)
EXAMPLE of Liquid Weight Conversion Formula: The Doctor ordered 650 mg of a medication. The vial contains 325 mg of the drug per 2 mL. How many milliliters should the patient receive?
Desired Dose = 650 mg
Dose on Hand = 325 mg
Vehiclee = 2 mL 325
650 divided by 325 = 2
2 x 2 mL (vehicle) = 4mL (amount to be administered)
Body Weight Formula
[Medications can be ordered based upon the weight of the patient. (ex. 100mg/kg of a drug)].
Desired Dose = Patient's Weight in Pounds divided by 2.2 pounds/kilograms x Dose divided by 1 kg
EXAMPLE of Body Weight Formula converted from Pounds to Kilograms: The doctor ordered 15 mg of a medication per kilogram of body weight. How many grams will the patient receive if he weighs 176 lbs?
Convert lbs to kg: 176 lbs divided by 2.2 lbs = 80 kg
80 (kilograms) x 15 mg (dose per kilogram) =
1200 mg or 1.2 grams (amount to administer)