GENTACIDIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for GENTACIDIN (GENTACIDIN).
Aminoglycoside antibiotic that binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting protein synthesis.
| Metabolism | Primarily excreted unchanged by glomerular filtration; minimal hepatic metabolism. |
| Excretion | Renal: 95-98% unchanged via glomerular filtration; biliary/fecal: <2%. |
| Half-life | 2-3 hours in adults with normal renal function; extended to 24-48 hours in anuria or severe renal impairment, requiring dose adjustment. |
| Protein binding | 10-20% bound to albumin. |
| Volume of Distribution | 0.2-0.4 L/kg, indicating distribution primarily in extracellular fluid. |
| Bioavailability | IM: 90-100%; topical: negligible systemic absorption (<10%); oral: <1%. |
| Onset of Action | IV: 15-30 min after infusion; IM: 1-2 hours; topical: variable, within 4-6 hours. |
| Duration of Action | 6-8 hours with normal renal function; prolonged in renal impairment; drug concentration-dependent. |
| Molecular Weight | 477.6 |
5-7 mg/kg IV every 24 hours.
| Dosage form | OINTMENT |
| Renal impairment | GFR >60 mL/min: 5-7 mg/kg q24h; GFR 30-59: 3-4 mg/kg q24-48h; GFR 15-29: 2-3 mg/kg q48-72h; GFR <15: 1-2 mg/kg q72-96h or after dialysis. |
| Liver impairment | No adjustment required for Child-Pugh A, B, or C; monitor levels if severe hepatic impairment. |
| Pediatric use | Neonates: 4-5 mg/kg IV q24h; Infants/Children: 5-7.5 mg/kg IV q24h; adjust per therapeutic drug monitoring. |
| Geriatric use | Initiate at lower end (5 mg/kg IV q24h) and adjust based on renal function; monitor serum creatinine and drug levels closely. |
| 1st trimester | Avoid use due to risk of fetal ototoxicity and nephrotoxicity. Use only for life-threatening infections when no safer alternative exists. |
| 2nd trimester | Use with caution. Monitor maternal renal function and drug levels. Risk of fetal harm outweighs benefits except in serious infections. |
| 3rd trimester | Avoid use near term due to potential for fetal nephrotoxicity and ototoxicity. Consider alternative agents. |
Clinical note
Comprehensive clinical and safety monograph for GENTACIDIN (GENTACIDIN).
| Placental transfer | Gentamicin crosses the placenta. Fetal serum concentrations are approximately 30-50% of maternal levels. Accumulation in fetal renal cortex and inner ear has been documented. |
| Breastfeeding | Gentamicin is excreted into breast milk in low concentrations. However, due to poor oral absorption from the infant gut, systemic effects are unlikely. Use with caution in breastfeeding women, especially if the infant has renal impairment or gastrointestinal disease. Monitor infant for diarrhea or rash. |
■ FDA Black Box Warning
WARNING: Nephrotoxicity and ototoxicity, even at therapeutic doses; monitor renal function and hearing. Neurotoxicity may occur. Avoid concurrent use with other nephrotoxic or ototoxic drugs.
| Serious Effects |
Hypersensitivity to gentamicin or any aminoglycosideMyasthenia gravis (risk of neuromuscular blockade)Pre-existing severe renal impairment (unless benefits outweigh risks)
| Precautions | Monitor renal function, serum drug levels, and audiometric tests. Use caution in elderly, dehydrated, or renally impaired patients. Prolonged use may lead to superinfection. |
| Food/Dietary | No specific food interactions; maintain adequate hydration to reduce renal risk. |
Loading safety data…
| Lactation Rating | L2 (Safe) |
| Teratogenic Risk | Gentamicin is an aminoglycoside antibiotic. Animal studies have shown evidence of fetal harm (nephrotoxicity, ototoxicity). There are no adequate well-controlled studies in pregnant women. Gentamicin crosses the placenta. Risk cannot be ruled out. The drug should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. First trimester: Theoretical risk of ototoxicity and nephrotoxicity. Second and third trimesters: Potential for fetal ototoxicity (eighth cranial nerve) and nephrotoxicity, especially with prolonged or high-dose therapy. |
| Fetal Monitoring | Maternal: Renal function (serum creatinine, BUN, urine output), serum drug concentrations (peak and trough), audiometric testing if prolonged therapy (baseline and periodic). Fetal/neonatal: No specific monitoring required unless signs of toxicity; consider auditory and renal assessment if high cumulative dose or prolonged exposure. |
| Fertility Effects | No well-controlled studies in humans. Animal studies have not reported adverse effects on fertility. However, generalized toxicity (e.g., renal impairment) could indirectly affect reproductive function. Use only when clearly indicated. |
| Clinical Pearls |
| Gentacidin (gentamicin sulfate) is an aminoglycoside antibiotic; monitor peak and trough levels to avoid nephrotoxicity and ototoxicity. Adjust dose in renal impairment. Avoid concurrent use with other nephrotoxic drugs (e.g., NSAIDs, vancomycin). |
| Patient Advice | Complete the full course even if symptoms improve. · Report hearing loss, tinnitus, dizziness, or decreased urine output immediately. · May cause injection site pain; rotate sites if applicable. · Avoid alcohol during therapy. |