Penicillin G Aqueous (Pfizerpen)

Category:

  • Antibiotic

Description:

  • Penicillin, Natural

Indications:

  • Meningococcal menigitis/septicemia

  • Actinomycosis

  • Clostridial infections (botulism, gas gangrene and tetanus)

  • Fusopirochetal infections

  • Rat-bite fever

  • Listeria infections

  • Pasteurella infections

  • Erysipeloid endocarditis

  • Diphtheria (adjunct to antitoxin to prevent carrier state)

  • Anthrax

  • Serious streptococcal infections

  • Syphilis (neurosyphilis)

  • Disseminated gonococcal infections

  • Lyme disease (non-FDA approved indication)

Contraindications:

  • None

Precautions:

  • Pregnancy category B

  • Use with caution in patients with penicillin or cephalosporin allergy (5-10% chance of cross-reactivity)

  • Counsel patient to finish all medication to prevent development of resistance

  • Intramuscular injection or continuous IV infusion are preferred routes of administration

  • Dosage modifications are generally only required in patients with severe renal impairment

Adverse Reactions (Side Effects):

  • Hypersensitivity

  • Gastrointestinal: nausea, vomiting, diarrhea

  • Vaginitis

 

Dosage:

Administered by injection (available in powder for injection and premixed/frozen)

  • Meningococcal menigitis/septicemia:

    • Adult: 24 million units per day (1-2 million units q2h)

    • Adult: 200,000-300,000 units/kg/day q2-4h in divided doses for 24 doses total

    • Children: 250,000 units/kg/day divided equally q4h for 7-14 days

  • Actinomycosis:

    • cervicofacial cases: 1-6 million units per day

    • thoracic/abdominal cases: 10-20 million units/day IV q4-6h for 6 weeks

  • Clostridial infections

    • 20 million units/day q4-6h

  • Fusopirochetal infections

    • 5-10 million units/day q4-6h

  • Rat-bite fever

    • Adult: 12-20 million units/day q4-6h for 3-4 weeks

    • Children: 150,000-250,000 units/kg/day divided equally q4h for 4 weeks

  • Listeria infections

    • 15-20 million units/day q4-6h for 2 weeks (menigitis) or 4 weeks (endocarditis)

  • Pasteurella infections

    • 4-6 million units/day q4-6h for 2 weeks

  • Erysipeloid endocarditis

    • 12-20 million units/day q4-6h for 4-6 weeks

  • Diphtheria

    • Adult: 2-3 million units/day q4-6h for 10-12 days

    • Children: 150,000-250,000 units/kg/day divided equally q6h for 7-10 days

  • Anthrax

    • minimum of 5 million units/day, may go up to 12-20 million units/day

  • Serious streptococcal infections

    • Adult: 5-24 million units/day q4-6h

    • Children: 150,000 units/kg/day divided equally q4-6h

  • Syphilis

    • 18-24 millions units/day (3-4 million units q4h) for 10-14 days

  • Disseminated gonococcal infections

    • Adult: 10 million units/day q4-6h

    • Children (<45 kg):

      • arthritis: 100,000 units/kg/day divided into 4 equal doses for 7-10 days

      • menigitis: 250,000 units/kg/day divided equally q4h for 10-14 days

      • endocarditis: 250,000 units/kg/day divided equally q4h for 4 weeks

    • Children (>45 kg):

      • arthritis, menigitis, endocarditis: 10 million units/day divided into 4 equal doses for duration of therapy

  • Lyme disease

    • use oral penicllin V for erythema chronicum migrans

    • 200,000-300,000 units/kg/day IV for 10-14 days

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