A patient weighing 22 lb requires 0.2 mg/kg. Which dose is closest to the calculated amount?

• A. 2 mg
• B. 22.2 mg
• C. 2.2 mg
• D. 22 mg

Answer: (A)

Weight-based dosing uses mg per kilogram of body weight. Convert the patient’s weight to kilograms: 22 lb is about 9.99 kg (roughly 10 kg). Multiply by the dosage: 0.2 mg/kg × 10 kg = 2 mg. So the calculated dose is about 2 mg, making 2 mg the closest option. The other numbers would require a heavier weight or a different per-kilogram dose and are not near the calculated 2 mg.