A nurse is preparing to administer digoxin 0.25 mg PO daily. The medication is available as 0.125 mg tablets. How many tablets should be administered?

A nurse is preparing to administer digoxin 0.25 mg PO daily. The medication is available as 0.125 mg tablets. How many tablets should be administered?

• A. 1 tablet
• B. 2 tablets
• C. 3 tablets
• D. 4 tablets

Answer: (B)

Dose calculation using tablet strength. To deliver 0.25 mg with tablets that contain 0.125 mg each, divide the prescribed dose by the tablet strength: 0.25 mg ÷ 0.125 mg per tablet = 2 tablets. Two tablets provide 2 × 0.125 mg = 0.25 mg, which matches the ordered dose exactly. This avoids under-dosing (one tablet would be 0.125 mg) and over-dosing (three or more tablets would exceed 0.25 mg). Keep in mind digoxin’s narrow therapeutic range, so verify the calculation carefully and administer only the prescribed amount.

Dose calculation using tablet strength. To deliver 0.25 mg with tablets that contain 0.125 mg each, divide the prescribed dose by the tablet strength: 0.25 mg ÷ 0.125 mg per tablet = 2 tablets. Two tablets provide 2 × 0.125 mg = 0.25 mg, which matches the ordered dose exactly. This avoids under-dosing (one tablet would be 0.125 mg) and over-dosing (three or more tablets would exceed 0.25 mg). Keep in mind digoxin’s narrow therapeutic range, so verify the calculation carefully and administer only the prescribed amount.