gentamisin

Gentamicin is an aminoglycoside antibiotic used to treat serious infections caused by predominantly Gram-negative bacteria. It is often given by injection and, in topical forms, used for certain wounds or burns. Because it is poorly absorbed from the gastrointestinal tract, oral use is limited to specific, non-systemic indications. Gentamicin is frequently used in combination with other antibiotics, such as beta-lactams, for synergistic effect in conditions like endocarditis or severe intra-abdominal infections.

Mechanism of action and spectrum: Gentamicin binds irreversibly to the 30S subunit of bacterial ribosomes, causing misreading of messenger RNA and blocking initiation of protein synthesis. This leads to bactericidal activity. Its effectiveness is greater against aerobic Gram-negative organisms, with limited activity against many Gram-positive organisms and anaerobes. Uptake into bacteria depends on oxygen, which can influence efficacy.

Administration and monitoring: Because systemic exposure is needed for efficacy, gentamicin is administered intravenously or intramuscularly for most infections. Dosing and interval scheduling depend on renal function, infection type, and patient weight. Therapeutic drug monitoring, including trough and sometimes peak levels, is commonly used to optimize efficacy while reducing toxicity. Topical gentamicin preparations are used for certain wounds, burns, or ocular infections.

Safety and resistance: Main concerns include nephrotoxicity and ototoxicity, which can be cumulative and partly irreversible. Neuromuscular blockade is a rare but potential adverse effect. Caution is advised in pregnancy and in patients with preexisting kidney impairment or hearing disorders. Resistance can arise through enzymatic inactivation, decreased uptake, or ribosomal mutations. Gentamicin remains a valuable option for specific severe infections when used with appropriate monitoring and risk assessment.