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 |
| Molecular Weight | 908.88 |
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 | Avoid. Animal studies show embryotoxicity and ototoxicity. Risk outweighs benefit. |
| 2nd trimester | Avoid. Potential for fetal ototoxicity and nephrotoxicity. Use only if clearly needed. |
| 3rd trimester | Avoid. Risk of fetal ototoxicity and nephrotoxicity, especially with prolonged therapy. |
Clinical note
Other nephrotoxic or ototoxic drugs increase risk of toxicity Can cause ototoxicity and nephrotoxicity with systemic use.
| FDA category | Animal |
| Placental transfer | Neomycin crosses the placenta in small amounts, but accumulation may occur with prolonged therapy. Potential for fetal ototoxicity. |
| Breastfeeding |
■ 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 aminoglycosideIntestinal obstructionInflammatory or ulcerative bowel disease (oral use)Myasthenia gravis (parenteral use)Concurrent use with other ototoxic or nephrotoxic drugs
| 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 |
Loading safety data…
| Neomycin is poorly absorbed orally, but limited data on excretion into breast milk. Minimal absorption from topical use. Consider benefit vs risk; monitor infant for diarrhea or rash. |
| Lactation Rating | L3 (Moderately Safe) |
| 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. |
| Food/Dietary | Oral neomycin may cause malabsorption of fat-soluble vitamins (A, D, E, K) and decrease absorption of oral vitamin B12, iron, and calcium. Avoid concurrent intake of dairy products, iron supplements, or antacids containing aluminum or magnesium within 2 hours of neomycin dose as they may interfere with absorption. For oral use, take with food to reduce GI upset, but note that food may slightly reduce absorption. |
| Clinical Pearls | Neomycin sulfate is an aminoglycoside antibiotic with poor oral absorption (~3%) but can accumulate in renal impairment; use with caution in patients with reduced GFR. Systemic absorption from topical or irrigating solutions may occur if applied to large wounds or burns. Prolonged use may lead to superinfection or Clostridium difficile colitis. Monitor renal function and hearing if used systemically or in high doses. Avoid concurrent use with other ototoxic or nephrotoxic drugs (e.g., loop diuretics, other aminoglycosides). For hepatic encephalopathy, neomycin reduces ammonia-producing gut flora but can cause malabsorption of fats and nutrients. |
| Patient Advice | Take this medication exactly as prescribed; do not use for longer than directed. · Oral neomycin is poorly absorbed but may cause stomach upset; take with food if needed. · Report any hearing loss, ringing in the ears, dizziness, or change in urination immediately. · Do not use neomycin to treat infections other than those specified by your doctor. · If using topical neomycin, avoid applying to large areas of broken skin unless directed. · Complete the full course of therapy even if symptoms improve to prevent resistance. · Inform your doctor if you have kidney disease, hearing problems, or neuromuscular disorders (e.g., myasthenia gravis). |