NEOMYCIN SULFATE
Clinical safety rating: safe
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
Aminoglycoside antibiotic that binds to the 30S ribosomal subunit, inhibiting protein synthesis and causing bacterial cell death by disrupting the cytoplasmic membrane.
| Metabolism | Minimally metabolized; primarily eliminated unchanged in urine via glomerular filtration. Oral neomycin is poorly absorbed and largely excreted unchanged in feces, with absorbed fraction metabolized to a limited extent. |
| Excretion | Renal (glomerular filtration) >90% unchanged; small amount biliary/fecal (<3%) |
| Half-life | 2-3 hours (normal renal function); prolonged to 20-60 hours in anuria |
| Protein binding | 0-30% (weak binding to albumin) |
| Volume of Distribution | 0.2-0.4 L/kg (low, predominantly extracellular fluid) |
| Bioavailability | Oral: <3% (minimal absorption); Topical: <1% (intact skin); Intramuscular: ~100% |
| Onset of Action | Oral: 1-2 hours (reduction of intestinal flora); Topical: 1-2 hours (bacterial suppression) |
| Duration of Action | Oral: 24-48 hours (intestinal antibacterial effect); Topical: 12-24 hours after application |
1-2 g orally 4 times daily (8-16 g/day) for hepatic encephalopathy or intraluminal infection; 0.5-1 g orally 4 times daily for preoperative bowel preparation.
| Dosage form | TABLET |
| Renal impairment | For systemic absorption (non-oral routes): GFR >50 mL/min: no adjustment; GFR 10-50 mL/min: 50% of dose or extend interval to 12-24h; GFR <10 mL/min: 25% of dose or 48-72h interval. For oral therapy (hepatic encephalopathy), limited absorption but caution; no specific guidelines but reduce dose or frequency if renal impairment. |
| Liver impairment | No adjustment required for Child-Pugh A or B; Child-Pugh C: no data, but use with caution due to potential nephrotoxicity. |
| Pediatric use | For hepatic encephalopathy: 50-100 mg/kg/day orally divided every 6-8 hours; maximum 12 g/day. For preoperative bowel preparation: 15-25 mg/kg/day divided every 6 hours. |
| Geriatric use | Start at lower end of dosing range; monitor renal function closely; consider age-related GFR decline; may require dose reduction per renal adjustment. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
| FDA category | Animal |
| Breastfeeding | Neomycin is poorly absorbed orally and is not expected to be excreted into breast milk in significant amounts. The M/P ratio is unknown due to inadequate data. Based on its low bioavailability, the American Academy of Pediatrics considers neomycin compatible with breastfeeding. However, caution is still recommended because of potential disruption of infant gut flora or direct toxicity if absorbed. Monitor infant for diarrhea or rash. |
■ FDA Black Box Warning
Warning: Aminoglycosides can cause nephrotoxicity, ototoxicity, and neuromuscular blockade. Neurotoxicity, including respiratory paralysis, may occur especially in patients with renal impairment or those receiving neuromuscular blocking agents. Neomycin sulfate is associated with a risk ofotoxicity and nephrotoxicity even with oral use due to systemic absorption.
| Common Effects | topical infections |
| Serious Effects |
["Hypersensitivity to neomycin or any aminoglycoside","Intestinal obstruction (oral use)","Pre-existing hearing loss or severe renal impairment (relative, depending on clinical situation)","History ofotoxicity or nephrotoxicity with prior aminoglycoside use (relative)"]
| Precautions | ["Monitor renal function (e.g., serum creatinine, BUN) and auditory function (audiometry) before and during therapy","Dose adjustment required in renal impairment","Avoid prolonged use due to risk of superinfection","Neuromuscular blockade risk: avoid concurrent use with anesthetics, muscle relaxants, or in patients with myasthenia gravis","Oral neomycin may cause intestinal malabsorption (steatorrhea) with high doses","Pregnancy risk category D; avoid unless essential","Use with caution in patients with neuromuscular disorders or electrolyte abnormalities"] |
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| Teratogenic Risk |
| Neomycin sulfate is an aminoglycoside antibiotic with low systemic absorption after oral administration. There are no adequate and well-controlled studies in pregnant women. Animal studies have shown evidence of fetal harm (ototoxicity and nephrotoxicity) at high parenteral doses. The risk of teratogenicity with oral neomycin is considered low due to poor absorption, but caution is advised. Avoid use in pregnancy unless clearly needed, especially during the first trimester. |
| Fetal Monitoring | Monitor maternal renal function (serum creatinine, BUN) and hearing (audiometry) if prolonged therapy is required. In neonates exposed in utero, monitor for signs of ototoxicity or nephrotoxicity. No specific fetal monitoring is routinely indicated for oral neomycin. |
| Fertility Effects | No specific data on human fertility effects. Animal studies with high parenteral doses have shown testicular atrophy and impaired spermatogenesis. Oral neomycin is unlikely to affect fertility due to minimal systemic absorption. |