From the Guidelines
Gentamicin is a potentially nephrotoxic and ototoxic aminoglycoside antibiotic that should be used with caution, particularly in patients with pre-existing renal failure or other underlying comorbidities, due to its potential to cause serious complications such as renal failure requiring hemodialysis 1.
Key Characteristics of Gentamicin
- Gentamicin is an aminoglycoside antibiotic used to treat various bacterial infections, particularly those caused by gram-negative bacteria.
- It works by binding to bacterial ribosomes and inhibiting protein synthesis, which kills the bacteria.
- Gentamicin is typically administered by injection (intravenous or intramuscular) or topically as eye drops, ear drops, or creams.
- Common dosing for adults with normal kidney function is 3-5 mg/kg/day, often divided into doses given every 8-24 hours depending on the infection severity and monitoring parameters.
Important Considerations for Gentamicin Use
- This medication requires careful monitoring of blood levels and kidney function as it can cause nephrotoxicity (kidney damage) and ototoxicity (hearing damage) 1.
- Gentamicin is particularly effective against organisms like Pseudomonas, E. coli, and other gram-negative bacteria, but has limited activity against anaerobes and gram-positive organisms.
- Due to its potential side effects, gentamicin is usually reserved for serious infections or used in combination with other antibiotics for synergistic effects.
Monitoring and Dosing Considerations
- In patients with normal renal function, it is reasonable to administer gentamicin every 8 hours with the dose adjusted to achieve a 1-hour serum concentration of ≈3 μg/mL and a trough concentration of <1 μg/mL 1.
- Increasing the dose of gentamicin in these patients did not result in enhanced efficacy but did increase the risk of nephrotoxicity.
- Therapeutic drug monitoring (TDM) should be performed during aminoglycoside treatment if available, especially when high dose is administered 1.
From the FDA Drug Label
Gentamicin sulfate, a water-soluble antibiotic of the aminoglycoside group, is derived by the growth of Micromonospora purpurea, an actinomycete. Gentamicin, an aminoglycoside, binds to the prokaryotic ribosome, inhibiting protein synthesis in susceptible bacteria. Gentamicin is an antibiotic of the aminoglycoside group, derived from the growth of Micromonospora purpurea, an actinomycete. It works by inhibiting protein synthesis in susceptible bacteria 2. Key points about gentamicin include:
- It is a water-soluble antibiotic 2
- It is used to treat bacterial infections
- It is bactericidal in vitro against Gram-positive and Gram-negative bacteria 2
From the Research
Definition and Mechanism of Gentamicin
- Gentamicin is an aminoglycoside antibiotic that acts by creating fissures in the outer membrane of the bacterial cell 3.
- It is particularly active against aerobic, gram-negative bacteria and acts synergistically against certain gram-positive organisms 3.
- Gentamicin is the most commonly used aminoglycoside, but amikacin may be particularly effective against resistant organisms 3.
Uses of Gentamicin
- Gentamicin is used in the treatment of severe infections of the abdomen and urinary tract, as well as bacteremia and endocarditis 3.
- It is also used for prophylaxis, especially against endocarditis 3.
Toxicity and Side Effects
- Gentamicin can cause ototoxicity (hearing loss) and nephrotoxicity (kidney damage) 4, 5, 6, 7.
- The risk of toxicity can be decreased by avoiding prolonged use, volume depletion, and concomitant administration of other potentially nephrotoxic agents 3.
- Single daily dosing of gentamicin may decrease the risk of toxicity compared to multiple daily dosing 4, 3.