A patient weighing 32 kg is prescribed 25 mg/kg/day in four equal doses. If the medication concentration is 100 mg/mL, how many milliliters are given per dose?

A patient weighing 32 kg is prescribed 25 mg/kg/day in four equal doses. If the medication concentration is 100 mg/mL, how many milliliters are given per dose?

• A. 1 mL
• B. 2 mL
• C. 3 mL
• D. 4 mL

Answer: (B)

The main idea is to translate the weight-based daily dose into a per-dose volume using the medication’s concentration. First, calculate the total daily dose: 25 mg/kg/day × 32 kg = 800 mg per day. Since this is given in four equal doses, each dose is 800 mg ÷ 4 = 200 mg per dose. With a concentration of 100 mg/mL, 200 mg corresponds to 200 mg ÷ (100 mg/mL) = 2 mL per dose. So, the patient should receive 2 mL per dose. If you gave 1 mL, that would be 100 mg per dose; 3 mL would be 300 mg per dose, etc., which would not meet the prescribed dose.

The main idea is to translate the weight-based daily dose into a per-dose volume using the medication’s concentration.

First, calculate the total daily dose: 25 mg/kg/day × 32 kg = 800 mg per day. Since this is given in four equal doses, each dose is 800 mg ÷ 4 = 200 mg per dose.

With a concentration of 100 mg/mL, 200 mg corresponds to 200 mg ÷ (100 mg/mL) = 2 mL per dose.

So, the patient should receive 2 mL per dose. If you gave 1 mL, that would be 100 mg per dose; 3 mL would be 300 mg per dose, etc., which would not meet the prescribed dose.