Products
Benzylpenicillin (penicillin G) is commercially available as an injectable (Penicillin Grünenthal).
Structure and properties
Benzylpenicillin (C16H18N2O4S, Mr = 334.4 g/mol) is present in the drug as benzylpenicillin sodium, a white crystalline powder that is very soluble in water. Other salts are also available. Benzylpenicillin is not acid stable, has low absorption, and therefore can only be administered parenterally. It is a natural product of -species.
Effects
Benzylpenicillin (ATC J01CE01) has bactericidal properties and is predominantly effective against Gram-positive pathogens. Effects are due to inhibition of bacterial transpeptidase, which disrupts cell wall formation. The half-life is short, ranging from 30 to 40 minutes.
Indications
For treatment of bacterial infectious diseases with susceptible pathogens.
Dosage
According to the SmPC. The drug is injected intravenously, infused, or administered intramuscularly.
Contraindications
- Hypersensitivity, including to other beta-lactam antibiotics.
Full precautions can be found in the drug label.
Interactions
Benzylpenicillin is excreted almost exclusively by the kidneys. It is both filtered and actively secreted. Drug-drug interactions have been described with the following substances. Many are organic anions:
- Bacteriostatic antibiotics
- Probenecid: inhibition of tubular secretion of penicillin.
- Salicylates, phenylbutazone, indomethacin, sulfinpyrazone.
- Methotrexate
- Hormonal contraceptives
Adverse effects
The most common possible adverse effects include hypersensitivity reactions, allergic skin reactions, administration site reactions, drug fever, oral mucositis, black hair tongue, nausea, vomiting, and diarrhea.
