Benzylpenicillin is a drug against gram positive and gram negative bacteria that are susceptible to the drug. It is also used in treating actinomycetes and spirochetes infections.

It inhibits final cross-linking stage of peptidoglycan production through binding and inactivation of transpeptidases on the inner surface of the bacterial cell membrane thus inhibiting bacterial cell wall synthesis.

Benzylpenicillin is used in the treatment of susceptible infections such as bacterial endocarditis, meningococcal meningitis and pneumococcal meningitis. It is also used in intrapartum prophylaxis against group B Streptoccocal infection in neonates.

Benzylpenicillin should not be used in those with hypersensitivity to benzylpenicillin and other penicillins.

Benzylpenicillin can bring about side effects such as the following:

  • Nausea
  • Vomiting
  • Stomatitis
  • Black or hairy tongue
  • Rash
  • Fever
  • Serum-like sickness
  • Convulsions
  • Interstitial nephritis
  • Haemolytic anaemia
  • Granulocytopenia
  • Agranulocytosis
  • Leucopenia
  • Thrombocytopenia
  • Anaphylaxis
  • Pseudomembranous colitis


Precautions of Benzylpenicillin include:

  • Patient with history of allergy esp β-lactam allergy and/or asthma, seizure disorder.
  • Diabetic patients.
  • Renal impairment.
  • Pregnancy and lactation



Benzylpenicillin may interact with the following medicines:

  • Oral contraceptives
  • Methotrexate
  • Probenecid
  • Bacteriostatic antibacterials (e.g. erythromycin, tetracyclines)

Symptoms of benzylpenicillin include the following:

  • Agitation
  • Confusion
  • Asterixis
  • Hallucinations
  • Stupor
  • Coma
  • Multifocal myoclonus
  • Seizures
  • Encephalopathy
  • Hyperkalaemia

Symptomatic and supportive treatment should be done.


Available Brands:

Common brands for Benzylpenicillin include:

  • COMBIPEN 4 Lac
  • PRONAPEN 4 Lac
  • PRONAPEN 8 Lac

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