An infant weighing 8 kg is prescribed cefdinir 25 mg/kg/day in divided doses every 6 hours. How many milligrams should be given per dose?

• A. 40 mg
• B. 50 mg
• C. 60 mg
• D. 70 mg

Answer: (B)

Dosing in pediatric patients is done by calculating the total daily amount from mg/kg/day and then dividing it into equal portions based on how often the medication is given.

For this infant: weight 8 kg and prescribed 25 mg per kg per day. Total daily dose = 8 kg × 25 mg/kg/day = 200 mg/day. The medication is given every 6 hours, which is 4 doses per day (24 hours ÷ 6 hours = 4). So each dose = 200 mg ÷ 4 = 50 mg per administration.

If you’re converting to mL using a suspension, 50 mg would correspond to the appropriate volume depending on concentration (for example, 125 mg/5 mL suspension gives 2 mL per 50 mg; 250 mg/5 mL suspension gives 1 mL per 50 mg).