NEBCIN
Clinical safety rating: caution
Comprehensive clinical and safety monograph for NEBCIN (NEBCIN).
Aminoglycoside antibiotic that binds to the 30S ribosomal subunit, causing misreading of mRNA and inhibiting bacterial protein synthesis.
| Metabolism | Primarily excreted unchanged by the kidneys via glomerular filtration; minimal hepatic metabolism. |
| Excretion | Renal excretion of unchanged drug accounts for >90% of elimination. Approximately 10% is excreted in bile. |
| Half-life | Terminal elimination half-life is 2-3 hours in patients with normal renal function. Prolonged to 24-48 hours in anuria. Clinical context: Dosing interval adjustment required in renal impairment to avoid toxicity. |
| Protein binding | Low, approximately 10-20%, primarily to albumin. |
| Volume of Distribution | 0.25-0.35 L/kg. Clinical meaning: Indicates distribution primarily into extracellular fluid; limited penetration into CSF and intracellular space. |
| Bioavailability | IM: nearly 100%; Oral: negligible (<1%) due to poor gastrointestinal absorption; Topical: minimal systemic absorption. |
| Onset of Action | IM: 30-60 minutes; IV: immediate (within minutes); Topical: variable, within 1-2 hours. |
| Duration of Action | Duration is 8-12 hours with IM or IV administration. Clinical notes: Peak serum levels occur 30-90 min after IM. Monitoring of trough and peak levels recommended. |
3-6 mg/kg/day IV in 2-3 divided doses every 8-12 hours; adjust based on serum levels and renal function.
| Dosage form | INJECTABLE |
| Renal impairment | CrCl 20-50 mL/min: 2-3 mg/kg every 12-24 hours. CrCl <20 mL/min: 2-3 mg/kg every 24-48 hours. Hemodialysis: 2-3 mg/kg post-dialysis. |
| Liver impairment | No specific Child-Pugh based adjustments; monitor serum levels and nephrotoxicity. |
| Pediatric use | Neonates: 4-6 mg/kg/day IV divided every 12 hours. Infants/Children: 6-7.5 mg/kg/day IV divided every 8 hours. |
| Geriatric use | Initial dose based on ideal body weight; adjust dosing interval based on renal function; target peak 5-10 mcg/mL, trough <2 mcg/mL. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for NEBCIN (NEBCIN).
| Breastfeeding | Tobramycin is excreted into human breast milk in low concentrations. The milk-to-plasma (M/P) ratio is approximately 0.2-0.4. Due to low oral bioavailability, systemic effects in the infant are unlikely, but caution is advised. Monitor the infant for diarrhea, candidiasis, and alteration in gut flora. Consider the developmental benefits of breastfeeding against the mother's clinical need. |
| Teratogenic Risk | NEBCIN (tobramycin) is an aminoglycoside antibiotic. In pregnancy, there is a potential risk of fetal ototoxicity and nephrotoxicity, particularly with high or prolonged exposure. Animal studies have shown evidence of fetal harm, but adequate human studies are limited. The drug should only be used in pregnancy if the potential benefit justifies the potential risk to the fetus. First trimester exposure may be associated with a slightly increased risk of congenital anomalies, but data are inconclusive. Second and third trimester exposure poses theoretical risks of fetal cranial nerve VIII damage and renal impairment. |
■ FDA Black Box Warning
Risk of nephrotoxicity and ototoxicity; risk of neuromuscular blockade and respiratory paralysis; risk of fetal harm if administered to pregnant women.
| Serious Effects |
Hypersensitivity to aminoglycosides; avoid in myasthenia gravis or other conditions predisposing to neuromuscular blockade.
| Precautions | Monitor renal function and drug levels; adjust dose in renal impairment; monitor for hearing loss; avoid concurrent use of nephrotoxic or ototoxic drugs; use caution in neuromuscular disorders. |
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| Fetal Monitoring | Monitor maternal renal function (serum creatinine, BUN, urinalysis), auditory function (audiometry for high-frequency hearing loss), and serum tobramycin levels (peak and trough) to avoid toxicity. In the fetus, consider ultrasound for growth and amniotic fluid volume if prolonged use. Assess for signs of fetal distress if maternal toxicity occurs. |
| Fertility Effects | No specific adverse effects on fertility have been reported in humans. Animal studies have not shown impairment of fertility. However, aminoglycosides can cause reproductive toxicity at high doses in animals, but human data are lacking. |