Benzathine Benzylpenicillin Injectable: Dosing
Long-acting benzathine benzylpenicillin guidance for syphilis, endemic treponematoses, tonsillitis, and rheumatic-fever prophylaxis.
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Source reviewed
source date listed on the source page
Guide category
Injectable drugs
Safety boundary
Prescription medicine information for clinician-guided use.
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Therapeutic action
Long-acting penicillin antibacterial.
Indications
- Early and late latent syphilis.
- Congenital syphilis without clinical signs in the neonate and adequate treatment in the mother.
- Endemic treponematoses such as yaws, bejel, and pinta.
- Streptococcal tonsillitis, prophylaxis of diphtheria, and primary and secondary prophylaxis of rheumatic fever.
Forms and strengths, route of administration
- Powder for injection in 1.2 MIU vial and 2.4 MIU vial, for IM injection only.
- Never for IV injection or infusion.
Dose
Syphilis
- Child: 50,000 IU/kg per injection, maximum 2.4 MIU per injection.
- Adult: 2.4 MIU per injection.
Yaws, bejel, pinta
- Child under 10 years: 1.2 MIU per injection.
- Child 10 years and over and adult: 2.4 MIU per injection.
Streptococcal tonsillitis, prophylaxis of diphtheria, prophylaxis of rheumatic fever
- Child under 30 kg: 600,000 IU per injection.
- Child 30 kg and over and adult: 1.2 MIU per injection.
Duration
- Early syphilis, congenital syphilis, tonsillitis, yaws, bejel, pinta, prophylaxis of diphtheria, primary prophylaxis of rheumatic fever: single dose.
- Late latent syphilis: one injection weekly for 3 weeks.
- Secondary prophylaxis of rheumatic fever: one injection every 4 weeks for several years.
Contra-indications, adverse effects, precautions
- Once reconstituted, suspension must be used immediately.
- Do not administer to penicillin-allergic patients.
- Administer with caution to patients allergic to cephalosporins and to patients with renal impairment.
- May cause gastrointestinal disturbances, pain at injection site, allergic reactions, Jarisch-Herxheimer reaction, convulsions in renal impairment or high doses, and symptoms of shock in case of accidental IV injection.
- Ensure that the IM injection does not enter a blood vessel.
- Do not combine with methotrexate.
- Pregnancy and breast-feeding: no contra-indication.
- Do not confuse long-acting benzathine benzylpenicillin for IM use with rapidly acting benzylpenicillin administered by IV route.
- Do not mix with other drugs in the same syringe.
Source
MSF Essential drugs practical guidelines (January 2026)
This page combines source-derived medicine reference sections with Kenza editorial context, while leaving out the Storage and Remarks sections from the source batch.
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