Procaine Penicillin Injectable: Dosing
Long-acting procaine benzylpenicillin guidance for diphtheria and congenital syphilis when oral treatment is not possible.
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Source reviewed
June 2025
Guide category
Injectable drugs
Safety boundary
Prescription medicine information for clinician-guided use.
Kenza Health Hub presents this medicine page as structured health education. Check dose, route, interactions, pregnancy or breast-feeding considerations, and local protocol with a qualified clinician or pharmacist. Read our medical editorial policy.
Therapeutic action
Long-acting penicillin antibacterial (12 to 24 hours).
Indications
- Diphtheria, when oral treatment is not possible.
- Congenital syphilis if the neonate has clinical signs or the mother did not receive adequate treatment during pregnancy.
Forms and strengths, route of administration
- Powder for injection in 0.6 MIU vial and 1.2 MIU vial, to be dissolved with the diluent supplied by the manufacturer.
- For IM injection only. Never administer by IV injection or infusion.
Dose
Diphtheria
- Child: 50,000 IU/kg once daily, maximum 1.2 MIU daily.
- Adult: 1.2 MIU once daily.
Congenital syphilis
- Neonate: 50,000 IU/kg once daily.
Duration
- Diphtheria: change to oral treatment as soon as the patient can swallow, to complete 14 days.
- Congenital syphilis: 10 days.
Contra-indications, adverse effects, precautions
- Once reconstituted, suspension must be used immediately.
- Do not administer to patients allergic to penicillin and or procaine.
- Administer with caution to patients allergic to cephalosporins or with renal impairment.
- May cause gastrointestinal disturbances and allergic reactions sometimes severe. In the event of allergic reactions, stop treatment immediately.
- Ensure that the needle does not accidentally enter a vessel.
- Pregnancy and breast-feeding: no contra-indication.
- Do not confuse procaine benzylpenicillin with short-acting benzylpenicillin administered several times per day 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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