Gentamicin — Compare Prices at US & Canada Pharmacies

Gentamicin is one of the oldest and most widely used aminoglycoside antibiotics, valued in hospitals for its fast, potent activity against Gram-negative bacteria — including Pseudomonas aeruginosa, E. coli, and Klebsiella — and for the synergy it provides when combined with a penicillin or vancomycin against certain Gram-positive infections like enterococcal endocarditis. WHO's AWaRe framework places it in the Access category: it's inexpensive, effective, and considered a first-line option for many serious infections precisely because it's been used safely and predictably for decades when dosed and monitored correctly.

That monitoring isn't optional. Gentamicin carries a boxed warning for nephrotoxicity and ototoxicity — kidney injury and permanent hearing or balance damage — risks that rise with higher doses, longer courses, pre-existing kidney impairment, and concurrent use of other drugs that stress the kidneys (such as NSAIDs, vancomycin, or contrast dye). Hospitals manage this by checking peak and trough drug levels in the blood and adjusting the dose to the individual patient's kidney function, often using extended-interval (once-daily) dosing regimens designed to maximize bacterial killing while limiting the drug's accumulation in the ear and kidney. Because these levels must be tracked closely, gentamicin is almost exclusively an inpatient or closely supervised outpatient-infusion drug rather than something taken unsupervised.

Ototoxicity from gentamicin can be irreversible and doesn't always resolve when the drug is stopped, which is why any new ringing in the ears, hearing loss, dizziness, or unsteadiness during treatment is treated as an urgent finding. The injection also contains sodium metabisulfite, a sulfite preservative that can trigger allergic-type reactions, including asthma flares, in sulfite-sensitive patients.

Boxed warning

BOXED WARNINGS Patients treated with aminoglycosides should be under close clinical observation because of the potential toxicity associated with their use. As with other aminoglycosides, gentamicin injection is potentially nephrotoxic. The risk of nephrotoxicity is greater in patients with impaired renal function and in those who receive high dosage of prolonged therapy. Neurotoxicity manifested by ototoxicity, both vestibular and auditory, can occur in patients treated with gentamicin, primarily in those with pre-existing renal damage and in patients with normal renal function treated with higher doses and/or for longer periods than recommended.

Contraindications

CONTRAINDICATIONS: Hypersensitivity to gentamicin is a contraindication to its use. A history of hypersensitivity or serious toxic reactions to other aminoglycosides may contraindicate use of gentamicin because of the known cross-sensitivity of patients to drugs in this class.

Warnings

WARNINGS: (See BOXED WARNINGS .) Contains sodium metabisulfite, a sulfite that may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in non-asthmatic people. Aminoglycosides can cause fetal harm when administered to a pregnant woman. Aminoglycoside antibiotics cross the placenta, and there have been several reports of total irreversible bilateral congenital deafness in children whose mothers received streptomycin during pregnancy.