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[Effects of aminoglycosides on the rabbit in-vivo ERG]
Abstract:
We evaluated the retinal toxicity of aminoglycosides (gentamicin, sisomicin, netilmicin, tobramycin and amikacin) by ERG, before and after a single-shot intravitreal injection in rabbits. Gentamicin 200 micrograms abolished the c-wave one week after injection, only slightly diminishing the b-wave and the oscillatory potentials (OPs). Gentamicin 80 micrograms did not alter the ERG up to at least 8 weeks after injection. All the ERG components examined were abolished by 200 micrograms and were irreversibly suppressed by 80 micrograms of sisomicin for the entire period of follow-up. Netilmicin (200 micrograms) or tobramycin (200 micrograms) transiently suppressed the b-wave, c-wave and the OPs. Amikacin (200 micrograms) caused no ERG changes for at least 8 weeks after injection. The clinical doses for single-shot intravitreal injections that we recommend are 100 micrograms for gentamicin, 200 micrograms for netilmicin, 200 micrograms for tobramycin and 200-400 micrograms for amikacin.
Insights
Aminoglycoside antibiotics can cause retinal toxicity. Sisomicin at 80 micrograms irreversibly damaged retinal function, while gentamicin and tobramycin showed dose-dependent effects in rabbit eyes.
Area of Science:
- Ophthalmology
- Toxicology
- Pharmacology
Context:
- Aminoglycosides are widely used antibiotics.
- Intravitreal injections are a common route for treating ocular infections.
- Evaluating the retinal safety of these drugs is crucial for clinical practice.
Purpose:
- To assess the retinal toxicity of five aminoglycosides (gentamicin, sisomicin, netilmicin, tobramycin, amikacin) via electroretinography (ERG).
- To determine safe dosage ranges for single-shot intravitreal injections in rabbits.
Summary:
- Single-shot intravitreal injections of varying aminoglycoside doses were administered to rabbits.
- High-dose gentamicin (200 µg) affected the c-wave, while sisomicin (80 µg) caused irreversible ERG suppression.
- Netilmicin and tobramycin (200 µg) caused transient ERG suppression; amikacin (200 µg) showed no ERG changes.
- Recommended clinical doses: gentamicin 100 µg, netilmicin 200 µg, tobramycin 200 µg, amikacin 200-400 µg.
Impact:
- Provides critical safety data for aminoglycoside use in ophthalmology.
- Informs clinical decisions on intravitreal antibiotic dosing to minimize retinal toxicity.
- Highlights the differential toxicity profiles among aminoglycosides, guiding therapeutic choices.