Pediatric Medication Dosage Calculation Practice

Posted on Mar 31, 2026 in Pharmacy

1. Tylenol Dosage Calculation

Order: 115 mg Tylenol Elixir.

Available: 80 mg/mL concentration.

  • a) Volume to draw up: 1.44 mL (115 mg / 80 mg/mL = 1.4375 mL).
  • b) Safety check: The safe dose is 10–15 mg/kg. The child weighs 20 lbs (9.1 kg). The safe range is 91–136.5 mg per dose. Yes, the order is safe.

2. Gentamycin Dosage and Concentration

Order: 60 mg IV q4h.

Available: 80 mg / 2 mL.

  • a) Volume to draw up: 1.5 mL (60 mg / 80 mg * 2 mL = 1.5 mL).
  • b) Final concentration in 50 mL bag: 1.2 mg/mL (60 mg / 50 mL = 1.2 mg/mL).

3. Ceftriaxone IV Administration

Order: 450 mg q12h IV. Patient weight: 17 kg.

Reconstitution: 100 mg/mL.

  • a) Volume to draw up: 4.5 mL (450 mg / 100 mg/mL = 4.5 mL).
  • b) Fluid rate: Total volume = 4.5 mL (med) + 20 mL (NS) + 20 mL (flush) = 44.5 mL. Rate = (44.5 mL / 20 min) * 60 min = 134 mL/hr.

4. Ceftazidime IV Administration

Order: 550 mg IV q8h. Patient weight: 42 lbs.

Reconstitution: 150 mg/mL.

  • a) Volume to draw up: 3.7 mL (550 mg / 150 mg/mL = 3.66 mL).
  • b) Fluid rate: Total volume = 3.7 mL (med) + 25 mL (diluent) + 20 mL (flush) = 48.7 mL. Rate = (48.7 mL / 30 min) * 60 min = 97 mL/hr.

5. Methylprednisolone Administration

Order: 15 mg IV q12h.

Available: 50 mg/mL.

Volume to administer: 0.3 mL (15 mg / 50 mg/mL = 0.3 mL).

6. Ampicillin Dosage Limits

Order: 430 mg IV q6h. Patient weight: 23 kg.

Recommended: 100–200 mg/kg/day divided q6h.

  • a) Minimum dose: 575 mg per dose (100 mg * 23 kg / 4 doses).
  • b) Maximum dose: 1150 mg per dose (200 mg * 23 kg / 4 doses).
  • c) Safety check: No, the ordered dose (430 mg) is below the recommended limit.

7. Azithromycin Dosage Limits

Order: 1150 mg IV q12h. Patient weight: 20 kg.

Recommended: 115–250 mg/kg/day divided in two doses.

  • a) Minimum dose: 1150 mg per dose (115 mg * 20 kg / 2 doses).
  • b) Maximum dose: 2500 mg per dose (250 mg * 20 kg / 2 doses).
  • c) Safety check: Yes, the dose is within the recommended limits.

8. Ibuprofen Dosage Calculation

Order: 150 mg PO q6h PRN. Patient weight: 15 kg.

Available: 50 mg / 8 mL.

  • a) Volume to draw up: 24 mL (150 mg / 50 mg * 8 mL = 24 mL).
  • b) Safety check: Yes, the dose is safe. The therapeutic range for 15 kg is 150–225 mg per dose.