Huelin is a long-acting antibiotic injection whose active ingredient is benzathine penicillin G, usually in a strength of 2.4 million international units (IU). It is given by deep intramuscular injection (i.e. into a muscle) and is particularly used in settings where a prolonged effect is desired. The formulation slowly releases penicillin over time, enabling sustained antibacterial action with a single dose. It is mostly used against susceptible bacteria, especially the streptococcal species and the organisms that cause syphilis, and also is used in prophylaxis (prevention) of certain infections like rheumatic fever.

Mechanism of Action:

• Benzathine penicillin G belongs to the beta-lactam class of antibiotics.

• It works by inhibiting bacterial cell wall synthesis. Specifically, it interferes with the enzymes (penicillin-binding proteins) that form cross-links in the peptidoglycan layer of bacterial cell walls.

• Without a proper cell wall, bacteria are unable to maintain structural integrity, leading to cell lysis (bursting) and death (so the drug is bactericidal).

  Uses:
  Some of the main indications include:

  • Treatment of syphilis (a sexually transmitted infection) in its various stages.

  • Treatment of certain skin infections, e.g. erysipelas, caused by streptococci.

  • Prevention of rheumatic fever in people who have had streptococcal throat infections or other streptococcal disease.

  • Sometimes used to prevent complications after streptococcal infection (like glomerulonephritis) and for other infections where long-acting penicillin is appropriate.

    Adverse Effects:
    Some side effects are mild and common, others are serious but rare.

    Common / Mild side effects may include:

    • Pain, swelling, redness at the injection site.

    • Allergic reactions like rash.

    • Gastrointestinal upset: diarrhoea, nausea.

    • Fungal overgrowth (e.g. candidiasis) sometimes when antibiotics upset normal flora.