- Gentamicin is one of the most widely used aminoglycoside antibiotics, particularly valued for its effectiveness against gram-negative bacterial infections. First isolated from Micromonospora purpurea in 1963, it remains a crucial antibiotic in modern medicine despite its potential toxicity risks.
- The primary clinical applications of gentamicin include treatment of serious gram-negative infections, particularly those caused by Pseudomonas aeruginosa, Enterobacteriaceae, and other aerobic gram-negative bacilli. It’s commonly used in combination therapy for conditions such as sepsis, pneumonia, complicated urinary tract infections, and endocarditis. In some regions, it’s also used topically for eye infections and burns.
- The pharmacokinetics of gentamicin make it unique. It must be administered parenterally (typically intravenously or intramuscularly) as it has poor oral absorption. The drug follows concentration-dependent killing, meaning higher peak concentrations result in better bacterial killing. This has led to the widespread adoption of once-daily dosing regimens, which can provide optimal therapeutic effects while potentially reducing toxicity risks.
- Dosing of gentamicin requires careful consideration of multiple factors, including the patient’s weight, renal function, and the specific infection being treated. Regular therapeutic drug monitoring is essential, with measurement of both peak and trough levels. The target peak levels typically range from 5-10 mg/L for conventional dosing, while trough levels should be below 2 mg/L to minimize toxicity risks.
- The major concerns with gentamicin use are its potential for nephrotoxicity and ototoxicity. Nephrotoxicity is usually reversible if detected early, but ototoxicity can be permanent, affecting both vestibular and auditory function. Risk factors for toxicity include advanced age, pre-existing renal dysfunction, prolonged therapy, and concurrent nephrotoxic medications. Regular monitoring of renal function, hearing tests, and vestibular function may be necessary during treatment.
