A 20kg weighted child is prescribed amoxicillin 25mg/kg/day orally in two divided doses. 250mg tablets are available, how many tablets will be given?

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2024

Explanation

The first step is to calculate the total daily dose by multiplying the child's weight by the prescribed dose per kilogram: 20 kg × 25 mg/kg/day = 500 mg/day.
Next, determine the amount for each individual dose. The prescription specifies 'two divided doses' (BD), so the total daily dose is divided by two: 500 mg / 2 = 250 mg per dose.
Finally, calculate the number of tablets needed for each dose. The desired dose (250 mg) is divided by the available tablet strength (250 mg): 250 mg / 250 mg = 1 tablet.
Therefore, the correct administration is 1 tablet given twice daily (BD).

Option B: This regimen provides 2 tablets twice a day, which equals 500 mg per dose and 1000 mg per day. This is double the prescribed total daily dose.
Option C: This regimen provides 2 tablets once a day (OD), which delivers the correct total daily dose of 500 mg but fails to follow the prescription's instruction for 'two divided doses'. Administering the entire dose at once can alter the drug's therapeutic levels and effectiveness.
Option D: This regimen provides 1 tablet once a day, which is only 250 mg per day. This is half of the required total daily dose of 500 mg.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pediatric Drug Dose Calculation as background academic context rather than a clinical decision trigger.
Accurate medication calculation is a critical nursing skill to ensure patient safety, especially in the pediatric population where there is a narrow margin for error.
The 'Five Rights' of Medication Administration (Right Patient, Right Drug, Right Dose, Right Route, Right Time) must always be followed. This question specifically tests the 'Right Dose' and 'Right Time' (frequency).
What if? If the child could not swallow tablets and a liquid suspension of 125 mg/5 mL was available instead, the calculation would change. The dose would still be 250 mg, but you would administer 10 mL of the suspension per dose ( (250 mg / 125 mg) * 5 mL = 10 mL ).

How to Approach the Question

First, identify all the given information: child's weight (20 kg), prescribed dose (25 mg/kg/day), frequency (two divided doses), and available medication strength (250 mg tablets).
Calculate the total required dose for the entire day by multiplying the weight by the mg/kg/day value.
Divide the total daily dose by the number of administrations per day (in this case, two) to find the amount for a single dose.
Use the 'Desired Dose over Have Dose' formula (Desired Dose / Available Dose) to determine how many tablets to give for that single dose.
Match your final answer (number of tablets and frequency) to the given options.

Concept Tested & Keywords

Concept Tested: Pediatric Drug Dose Calculation
Stem keywords: 20kg child, amoxicillin, 25mg/kg/day, two divided doses, 250mg tablets
Lead-in keywords: how many tablets
Clinical cues: Age/sex group narrows the expected diagnosis, intervention, or normal reference range.

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E6 Pharmacology Nurses Shanbhag 3e p. 51-53

E6 Nursing Fundamentals Potter Perry 12e Part 3 pp. 141-143, 142-144

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