Bicillin Dosing for a 2-Year-Old (11.25 kg) Unable to Take Oral Medication
Recommended Dose
For a 2-year-old weighing 11.25 kg who cannot take oral medication, administer Benzathine penicillin G (Bicillin) 562,500 units (50,000 units/kg) as a single intramuscular injection. 1
Dosing Calculation and Rationale
Weight-based dosing: The standard pediatric dose for benzathine penicillin is 50,000 units/kg body weight for a single IM dose 1
For this patient: 11.25 kg × 50,000 units/kg = 562,500 units
Maximum dose: Do not exceed 2.4 million units per dose 1
Clinical Context and Indication
The evidence provided specifically addresses benzathine penicillin dosing for:
Early-stage syphilis (primary, secondary, early latent): Single IM dose of 50,000 units/kg (max 2.4 million units) 1
Late latent syphilis: Would require 50,000 units/kg IM once weekly for 3 doses (total 150,000 units/kg; max 7.2 million units) 1
Administration Considerations
IM injection is painful and the patient/family should be counseled accordingly 2
Single dose administration is appropriate for early-stage disease 1
The formulation is specifically designed for IM use when oral administration is not feasible 1
Important Caveats
If this patient has congenital syphilis or neurosyphilis, benzathine penicillin is NOT appropriate—aqueous crystalline penicillin G IV would be required instead 1
For congenital disease, dosing would be 100,000-150,000 units/kg/day IV divided every 8-12 hours for 10 days 1
The specific indication (streptococcal pharyngitis, syphilis prophylaxis, etc.) should guide whether this single-dose regimen is appropriate versus alternative penicillin formulations 1