Natriumbenzylpenicilline Sandoz (Benzylpenicillin)

Benzylpenicillin is a beta‑lactam antibiotic used to treat infections caused by susceptible bacteria. It is employed across several clinical indications:

• Meningitis: rapid bacterial eradication in the central nervous system.
• Endocarditis: eradication of streptococcal or staphylococcal organisms from heart valves.
• Pneumonia: treatment of community‑acquired bacterial lung infection.
• Skin and soft‑tissue infections: resolution of cellulitis and wound infections.
• Syphilis (early): elimination of Treponema pallidum in early disease stages.

• Benzylpenicillin inhibits bacterial cell‑wall synthesis by binding to penicillin‑binding proteins (PBPs) that catalyze the cross‑linking of peptidoglycan strands. This binding blocks transpeptidation, weakening the cell wall and leading to osmotic lysis of susceptible Gram‑positive and some Gram‑negative bacteria.

Benzylpenicillin may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Injection site pain: discomfort at the site of intramuscular or intravenous administration.
• Diarrhea: mild to moderate loose stools.
• Nausea: occasional feeling of queasiness.
• Rash: transient erythematous skin eruptions.
• Elevated liver enzymes: mild, transient increase in hepatic transaminases.

Serious or Rare Side Effects

• Anaphylaxis: severe, potentially life‑threatening allergic reaction.
• Severe neutropenia: marked reduction in neutrophil count.
• Clostridioides difficile colitis: antibiotic‑associated colitis.
• Serum sickness‑like reaction: fever, arthralgia, and rash.
• Acute interstitial nephritis: inflammation of renal interstitium.

When using Benzylpenicillin, several safety considerations are recommended:

• Assess allergy: verify no history of penicillin hypersensitivity before administration.
• Monitor renal function: adjust dosing in patients with impaired kidney function.
• Observe for superinfection: watch for fungal overgrowth during prolonged therapy.
• Use with caution in pregnancy: limited safety data; weigh benefits against potential risks.
• Store at 2‑8 °C: keep refrigerated, protect from light, do not freeze.

Benzylpenicillin can interact with other medicines, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• Probenecid: decreases renal excretion, raising penicillin levels and risk of toxicity.
• Methotrexate: impaired clearance may lead to severe myelosuppression.

Moderate Interactions (Monitor Closely)

• Oral contraceptives: possible reduction in hormonal effectiveness; consider backup contraception.
• Warfarin: enhanced anticoagulant effect; monitor INR more frequently.
• Live vaccines: may diminish vaccine efficacy; assess timing relative to antibiotic therapy.