The medication order is amoxicillin 125 mg PO for otitis media. The supply on hand is amoxicillin suspension 250 mg/5 mL. What amount should be given?

The medication order is amoxicillin 125 mg PO for otitis media. The supply on hand is amoxicillin suspension 250 mg/5 mL. What amount should be given?

• A. 3 mL
• B. 2.5 mL
• C. 2 mL
• D. 2.0 mL

Answer: (B)

Understanding how to dose a liquid antibiotic: you convert the suspension’s strength to mg per mL and then compute the volume needed for the prescribed mg. The suspension is 250 mg in 5 mL, which is 50 mg per mL. To deliver 125 mg, divide 125 mg by 50 mg/mL, giving 2.5 mL. You can also see this as half of 250 mg is needed, and half of 5 mL is 2.5 mL, so that volume provides 125 mg. For context, 3 mL would be 150 mg, and 2 mL would be 100 mg, so 2.5 mL is the correct amount.

Understanding how to dose a liquid antibiotic: you convert the suspension’s strength to mg per mL and then compute the volume needed for the prescribed mg.

The suspension is 250 mg in 5 mL, which is 50 mg per mL. To deliver 125 mg, divide 125 mg by 50 mg/mL, giving 2.5 mL. You can also see this as half of 250 mg is needed, and half of 5 mL is 2.5 mL, so that volume provides 125 mg.

For context, 3 mL would be 150 mg, and 2 mL would be 100 mg, so 2.5 mL is the correct amount.