gentamysiini

Gentamycins, commonly referred to as gentamicin, are a group of aminoglycoside antibiotics produced by soil actinomycetes (notably Micromonospora species). The pharmaceutical product is a mixture that mainly includes Gentamicin C1, C1a, and C2. They are used to treat serious infections caused by susceptible aerobic Gram-negative bacteria and are often employed in combination with other antibiotics for a broader or synergistic effect. Their activity against Gram-positive organisms is limited unless used with a beta-lactam antibiotic.

Mechanism of action involves binding irreversibly to the 30S subunit of bacterial ribosomes, causing misreading of mRNA and inhibition of initiation of protein synthesis. This leads to bactericidal effects, particularly against aerobic Gram-negative pathogens. They are poorly active against anaerobes and have limited activity in environments with low oxygen tension.

Administration and pharmacokinetics: Gentamycins are typically given parenterally for systemic infections due to poor oral bioavailability. They can be used topically or ophthalmically for localized infections. They distribute into body fluids but do not cross the blood–brain barrier well. They are primarily eliminated by the kidneys, necessitating dose adjustments in renal impairment and careful monitoring of drug levels to minimize toxicity.

Clinical use and safety: Gentamicin is used for severe nosocomial infections, complicated urinary tract infections, certain pneumonias, intra-abdominal infections, gynecological infections, and as an adjunctive agent in endocarditis caused by susceptible organisms. The main adverse effects are nephrotoxicity and ototoxicity (cochlear and vestibular), which can be irreversible with prolonged therapy. Neuromuscular blockade is a rare but potential risk. Risk increases with higher trough levels, longer treatment duration, and concomitant nephrotoxic or ototoxic drugs.

Resistance and regulation: Bacterial resistance arises mainly from aminoglycoside-modifying enzymes and, less commonly, ribosomal target alterations. Resistance mechanisms and pharmacovigilance influence clinical use and dosing guidelines.