Name Benzyl Penicillin
Classes Antiinfective Agent
Antibiotic
Penicillin
Diseases Actinomycosis
Anthrax
Arthritis
Infectious Disease
Neurosyphillis
Pneumonia

Benzyl Penicillin

Benzyl Penicillin belongs to the class of antibiotics known as beta-lactam antibiotics. It acts by inhibiting bacterial cell wall synthesis, specifically targeting the enzyme transpeptidase. This mechanism weakens the bacterial cell wall, leading to cell lysis and eventual death of the bacteria.

Benzyl Penicillin is indicated for the treatment of various bacterial infections caused by susceptible organisms. Common indications include respiratory tract infections, skin and soft tissue infections, bacterial endocarditis, and syphilis. The drug is effective against a broad spectrum of Gram-positive bacteria.

Streptococcal (Group A) Upper Respiratory Infections (for example, pharyngitis)

  • Adults: a single injection of 1,200,000 units
  • Older pediatric patients: a single injection of 900,000 units
  • Infants and pediatric patients under 60 lbs: 300,000 to 600,000 units.  

Syphilis

  • Primary, secondary, and latent—2,400,000 units (1 dose).
  • Late (tertiary and neurosyphilis)— 2,400,000 units at 7-day intervals for three doses.
  • Congenital—under 2 years of age: 50,000 units/kg/body weight;
  • Ages 2 to 12 years: adjust dosage based on adult dosage schedule.  

Yaws, Bejel, and Pinta—1,200,000 units (1 injection).  

Prophylaxis—for rheumatic fever and glomerulonephritis. Following an acute attack, penicillin G benzathine (parenteral) may be given in doses of 1,200,000 units once a month or 600,000 units every 2 weeks. 

Common adverse reactions associated with Benzyl Penicillin include:

  • Gastrointestinal disturbances (nausea, vomiting, diarrhea)
  • Hypersensitivity reactions (rash, itching)
  • Pain at the injection site
  • Fever
  • Hematologic effects (eosinophilia)

Less common adverse reactions may include anaphylaxis, superinfections, and renal impairment.

  • Hypersensitivity Reactions: Benzyl Penicillin can cause severe allergic reactions, including anaphylaxis. Patients with a history of penicillin allergy should be closely monitored.
  • Superinfections: Prolonged use may result in overgrowth of non-susceptible organisms. Appropriate measures should be taken if superinfections occur.
  • Renal Impairment: Dosage adjustment is necessary in patients with impaired renal function to prevent toxicity.

Contraindication

Benzyl Penicillin is contraindicated in individuals with a history of severe hypersensitivity reactions to penicillins or cephalosporins.