Certified Medical Assistant (CMA AAMA)PharmacologyHard
A physician orders a medication at 5 mg/kg for a patient who weighs 154 lb. How many milligrams should the medical assistant prepare?
- A350 mg
- B154 mg
- C70 mg
- D770 mg
Show answer & explanationAnswer & explanation
Correct answer: A. 350 mg
First convert pounds to kilograms: 154 lb ÷ 2.2 = 70 kg. Then multiply by the ordered dose: 70 kg × 5 mg/kg = 350 mg. Therefore, the medical assistant should prepare 350 mg.
Why the other options are wrong
- B. This is the patient's weight in pounds, not the correct calculated dose in mg.
- C. This is the patient's weight in kilograms, not the calculated dose.
- D. This results from multiplying the weight in pounds by the mg/kg rate without converting to kilograms first.
Weight-Based Dosage Calculation
Calculating medication dose based on patient weight requires converting pounds to kilograms before multiplying by the mg/kg order.
- 1 kg = 2.2 lb
- Formula: (Weight in lb ÷ 2.2) x mg/kg ordered
- Always convert units before calculating final dose
Memory trick: 'Divide by 2.2 before you multiply'