A client weighs 158 lb and receives tobramycin IM at 6.6 mg/kg daily. The concentration is 10 mg/mL. How many milliliters per dose are required?

A client weighs 158 lb and receives tobramycin IM at 6.6 mg/kg daily. The concentration is 10 mg/mL. How many milliliters per dose are required?

• A. 24.0 mL
• B. 37.4 mL
• C. 47.4 mL
• D. 57.6 mL

Answer: (C)

This question tests converting weight to kilograms, applying mg per kg to get the total milligrams per dose, and then converting milligrams to milliliters using the drug’s concentration. First, convert weight: 158 lb divided by 2.2046 equals about 71.8 kg. Multiply by the dose per kg: 71.8 × 6.6 mg/kg ≈ 473.9 mg per day. With a concentration of 10 mg/mL, the volume needed is 473.9 mg ÷ 10 mg/mL ≈ 47.4 mL per dose. Since the dosing is daily, that is the milliliters per dose.

This question tests converting weight to kilograms, applying mg per kg to get the total milligrams per dose, and then converting milligrams to milliliters using the drug’s concentration.

First, convert weight: 158 lb divided by 2.2046 equals about 71.8 kg. Multiply by the dose per kg: 71.8 × 6.6 mg/kg ≈ 473.9 mg per day. With a concentration of 10 mg/mL, the volume needed is 473.9 mg ÷ 10 mg/mL ≈ 47.4 mL per dose. Since the dosing is daily, that is the milliliters per dose.