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    Prescription under medical supervision


    This penicillin should be administered in a hospital setting (injections every 4 to 6 hours).


    Therapeutic action

    • Short-acting penicillin antibacterial


    • Diphtheria, neurosyphilis
    • Congenital syphilis (presence of clinical signs in the neonate and lack of adequate treatment in the mother)

    Forms and strengths, route of administration

    • Powder for injection in vials of:
      • 1 MIU (600 mg), to be dissolved in 2 ml of water for injection or 0.9% sodium chloride
      • 5 MIU (3 g), to be dissolved in 5 ml of water for injection or 0.9% sodium chloride
    • For IM injection or slow IV injection through an infusion tube (3 to 5 minutes) or infusion (60 minutes) in 0.9% sodium chloride or 5% glucose.



    • Child: 50 000 IU (30 mg)/kg every 6 hours (max. 4 MIU or 2.4 g daily)
    • Adult: 1 MIU (600 mg) every 6 hours



    • Adult: 2 to 4 MIU (1.2 to 2.4 g) by IV injection every 4 hours


    Congenital syphilis

    • 50 000 IU (30 mg)/kg by IV injection every 12 hours from D1 to D7, then
    • 50 000 IU (30 mg)/kg by IV injection every 8 hours from D8 to D10


    • Diphtheria, neurosyphilis: 14 days
    • Congenital syphilis: 10 days


    For diphtheria, change to oral route as soon as possible.

    Contra-indications, adverse effects, precautions

    • Do not administer to penicillin-allergic patients.
    • Administer with caution to patients allergic to cephalosporins (cross-sensitivity may occur) and renal impairment (reduce dosage in patients with neurosyphilis).
    • May cause:
      • gastroinstestinal disturbances, pain at injection site, anaemia, allergic reactions sometimes severe;
      • Jarisch-Herxheimer reaction (fever, chills, myalgia, tachycardia) in patients with syphilis;
      • convulsions in the event of rapid IV injection, high dosages or renal impairment.
    • Do not combine with methotrexate.
    • Pregnancy: no contra-indication
    • Breast-feeding: no contra-indication


    • Do not confuse short-acting benzylpenicillin, administered several times a day by IV route, with long-acting penicillins (benzathine benzylpenicillin and procaine benzylpenicillin) administered by IM route only.
    • Do not mix with other drugs in the same syringe or infusion.


    – Below 25 °C
    Once reconstituted, suspension must be used immediately.