Version July 2025
Systemic absorption of neomycin occurs following oral administration, and toxic reactions may occur. Patients treated with neomycin should be under close clinical observation because of the potential toxicity associated with the use of neomycin. Neurotoxicity (including ototoxicity) and nephrotoxicity following the oral use of neomycin sulfate have been reported, even when used in recommended doses. The potential for nephrotoxicity, permanent bilateral auditory ototoxicity, and sometimes vestibular toxicity, is present in patients with healthy renal function when treated with higher doses of neomycin or for longer periods than recommended. Serial, vestibular and audiometric tests, as well as tests of renal function, should be performed (especially in high-risk patients). The risk of nephrotoxicity and ototoxicity is greater in patients with impaired renal function. Ototoxicity is often delayed in onset, and patients developing cochlear damage will not have symptoms during therapy to warn them of developing eighth nerve destruction, and total or partial deafness may occur long after neomycin has been discontinued.
Other factors which increase the risk of toxicity are advanced age and dehydration.
Neuromuscular blockage and respiratory paralysis have been reported following the oral use of neomycin. The possibility of the occurrence of neuromuscular blockage and respiratory paralysis should be considered if neomycin is administered, especially to patients receiving anesthetics; neuromuscular-blocking agents such as tubocurarine, succinylcholine, decamethonium; or massive transfusions of citrate anticoagulated blood. If blockage occurs, calcium salts may reverse these phenomena, but mechanical respiratory assistance may be necessary.
Concurrent or sequential systemic, oral or topical use of other aminoglycosides, including paromomycin and other potentially nephrotoxic or neurotoxic drugs such as bacitracin, cisplatin, vancomycin, amphotericin B, polymyxin B, colistin and viomycin, should be avoided because the toxicity may be additive.
The concurrent use of neomycin with potent diuretics such as ethacrynic acid or furosemide should be avoided, since certain diuretics by themselves may cause ototoxicity. In addition, when administered intravenously (IV), diuretics may enhance neomycin toxicity by altering the antibiotic concentration in serum and tissue.
Note: Dosage expressed in terms of neomycin sulfate.
Note: Dosage expressed in terms of neomycin sulfate.
Cholangitis, prophylaxis of recurrent episodes after Kasai portoenterostomy: Limited data available:
Infants and Children ≤3 years: Oral: 25 to 50 mg/kg/day in 4 divided doses 4 days per week; continue until 2 to 3 years of age. Dosing based on two small randomized trials and a small case series (Ref).
Enteric bacteria eradication (including gut flora): Limited data available: Note: Use of neomycin for the treatment of enteric infection has been replaced by other agents (Ref).
Infants, Children, and Adolescents: Oral: 50 to 100 mg/kg/day in divided doses every 6 to 8 hours; maximum daily dose: 12 g/day (Ref); duration of treatment should not exceed 2 weeks due to GI absorption, which may result in systemic toxicities (Ref).
Surgical prophylaxis, colorectal: Limited data available: Infants, Children, and Adolescents: Oral: 15 mg/kg/dose for 3 doses administered over 10 hours (eg, at 1 PM, 2 PM, and 11 PM) the day before surgery as part of an appropriate combination regimen, with or without mechanical bowel preparation (consult institutional protocol); maximum dose: 1,000 mg/dose (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no specific dosing adjustments provided in the manufacturer's labeling; however, based on experience with aminoglycosides in pediatric patients, renal impairment increases the risk for toxicity, and consideration should be given to reducing the dose or discontinuing therapy. Dialyzable.
There are no dosing adjustments provided in the manufacturer's labeling.
(For additional information see "Neomycin: Drug information")
Small intestinal bacterial overgrowth, methanogen overgrowth (off-label use): Oral: 500 mg twice daily, in combination with rifaximin, for 14 days (Ref).
Surgical prophylaxis, colorectal: Oral: 1 g at 1 PM, 2 PM, and 11 PM on the day preceding 8 AM surgery in combination with other appropriate agents and as an adjunct to mechanical cleansing of the intestine, followed by an appropriate IV antibiotic prophylaxis regimen (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in manufacturer’s labeling; however, dosage reduction or discontinuation of therapy should be considered if a patient develops renal insufficiency. The risk of nephro- and/or ototoxicity is increased in patients with renal impairment.
There are no dosage adjustments provided in manufacturer’s labeling.
The following adverse drug reactions are derived from product labeling unless otherwise specified.
Frequency not defined: Gastrointestinal: Diarrhea, nausea, vomiting
Postmarketing:
Dermatologic: Contact dermatitis (systemic contact dermatitis) (Carnicle 2020)
Gastrointestinal: Clostridioides difficile colitis (Bolton 1979), malabsorption syndrome (with prolonged therapy)
Nervous system: Neurotoxicity
Neuromuscular & skeletal: State of neuromuscular blockade
Otic: Ototoxicity (including auditory ototoxicity and vestibular ototoxicity) (Ward 1978)
Renal: Nephrotoxicity
Respiratory: Respiratory paralysis
Hypersensitivity to the neomycin or any component of the formulation; intestinal obstruction; patients with inflammatory or ulcerative GI disease.
Concerns related to adverse effects:
• Hypersensitivity: Cross-sensitivity to other aminoglycosides may occur.
• Malabsorption: Small amounts of neomycin are absorbed through intact intestinal mucosa; increases in fecal bile acid excretion and reduction of intestinal lactase activity may occur. Oral doses of >12 g/day produce malabsorption of fats, nitrogen, cholesterol, carotene, glucose, xylose, lactose, sodium, calcium, cyanocobalamin and iron.
• Nephrotoxicity: [US Boxed Warning]: May cause nephrotoxicity; usual risk factors include preexisting renal impairment, concomitant nephrotoxic medications, advanced age and dehydration. Discontinue treatment if signs of nephrotoxicity occur; renal damage is usually reversible.
• Neuromuscular blockade and respiratory paralysis: [US Boxed Warning]: May cause neuromuscular blockade and respiratory paralysis; especially when given soon after anesthesia or muscle relaxants.
• Neurotoxicity: [US Boxed Warning]: May cause neurotoxicity; symptoms also include numbness, skin tingling, muscle twitching and seizures. Usual risk factors include preexisting renal impairment and concomitant neuro-/nephrotoxic medications. Discontinue treatment if signs of ototoxicity occur; risk of hearing loss continues after drug withdrawal.
• Superinfection: Prolonged use may result in fungal or bacterial superinfection, including C. difficile-associated diarrhea (CDAD) and pseudomembranous colitis; CDAD has been observed >2 months postantibiotic treatment.
Disease-related concerns:
• Hearing impairment: Use with caution in patients with preexisting vertigo, tinnitus, or hearing loss.
• Neuromuscular disorders: Use with caution in patients with neuromuscular disorders, including myasthenia gravis and Parkinson disease.
• Renal impairment: Use with caution in patients with preexisting renal insufficiency; dosage modification required.
Special populations:
• Patients with genomic variants in MT-RNR1: Carriers of certain variants in the MT-RNR1 gene (eg, m.1555A>G) may be at increased risk for aminoglycoside-induced ototoxicity, including potentially significant hearing loss that may be irreversible, even when serum levels are within the normal range.
Dosage form specific issues:
• Benzyl alcohol and derivatives: Some dosage forms may contain sodium benzoate/benzoic acid; benzoic acid (benzoate) is a metabolite of benzyl alcohol; large amounts of benzyl alcohol (≥99 mg/kg/day) have been associated with a potentially fatal toxicity (“gasping syndrome”) in neonates; the “gasping syndrome” consists of metabolic acidosis, respiratory distress, gasping respirations, CNS dysfunction (including convulsions, intracranial hemorrhage), hypotension, and cardiovascular collapse (AAP ["Inactive" 1997]; CDC 1982); some data suggests that benzoate displaces bilirubin from protein binding sites (Ahlfors 2001); avoid or use dosage forms containing benzyl alcohol derivative with caution in neonates. See manufacturer's labeling.
Other warnings/precautions:
• Parenteral administration: More toxic than other aminoglycosides when given parenterally; do not administer parenterally.
• Surgical irrigation: Do not use as surgical irrigation due to significant systemic absorption of the drug.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling.
Tablet, Oral, as sulfate:
Generic: 500 mg
Yes
Tablets (Neomycin Sulfate Oral)
500 mg (per each): $1.49 - $1.98
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Each 500 mg neomycin sulfate tablet contains 350 mg of neomycin base.
Oral: Administer without regard to meals; for surgical prophylaxis, administer at prescribed dosing times.
Store at 20ºC to 25ºC (68ºF to 77ºF).
Adjunct therapy (with erythromycin) for the suppression of normal bacterial flora of the bowel (eg, preoperative preparation); adjunct therapy for hepatic coma (portal-systemic encephalopathy) by reducing ammonia-forming bacteria in the intestinal tract (All indications: FDA approved in ages ≥18 years and adults).
None known.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program
Aminoglycosides: May increase nephrotoxic effects of Aminoglycosides. Aminoglycosides may increase neurotoxic effects of Aminoglycosides. Risk X: Avoid
Amphotericin B: May increase nephrotoxic effects of Aminoglycosides. Amphotericin B may increase neurotoxic effects of Aminoglycosides. Risk C: Monitor
Ataluren: May increase adverse/toxic effects of Aminoglycosides. Specifically, an increased risk of nephrotoxicity may occur with the concomitant use of ataluren and aminoglycosides. Risk X: Avoid
Bacillus clausii: Antibiotics may decrease therapeutic effects of Bacillus clausii. Management: Bacillus clausii should be taken in between antibiotic doses during concomitant therapy. Risk D: Consider Therapy Modification
Bacitracin (Systemic): Neomycin (Systemic) may increase nephrotoxic effects of Bacitracin (Systemic). Risk X: Avoid
Bisphosphonate Derivatives: Aminoglycosides may increase hypocalcemic effects of Bisphosphonate Derivatives. Aminoglycosides may increase nephrotoxic effects of Bisphosphonate Derivatives. Risk C: Monitor
Botulinum Toxin-Containing Products: Aminoglycosides may increase neuromuscular-blocking effects of Botulinum Toxin-Containing Products. Risk C: Monitor
Capreomycin: May increase neuromuscular-blocking effects of Aminoglycosides. Risk C: Monitor
CARBOplatin: Aminoglycosides may increase ototoxic effects of CARBOplatin. Especially with higher doses of carboplatin. CARBOplatin may increase nephrotoxic effects of Aminoglycosides. Risk C: Monitor
Cardiac Glycosides: Aminoglycosides may decrease serum concentration of Cardiac Glycosides. This effect has only been demonstrated with oral aminoglycoside administration. Risk C: Monitor
Cephalosporins: May increase nephrotoxic effects of Aminoglycosides. Cephalosporins may decrease serum concentration of Aminoglycosides. Risk C: Monitor
Cholera Vaccine: Antibiotics may decrease therapeutic effects of Cholera Vaccine. Management: Avoid cholera vaccine in patients receiving systemic antibiotics, and within 14 days following the use of oral or parenteral antibiotics. Risk X: Avoid
CISplatin: May increase nephrotoxic effects of Aminoglycosides. CISplatin may increase neurotoxic effects of Aminoglycosides. Risk X: Avoid
Colistimethate: Aminoglycosides may increase nephrotoxic effects of Colistimethate. Aminoglycosides may increase neuromuscular-blocking effects of Colistimethate. Management: Avoid coadministration of colistimethate and aminoglycosides whenever possible due to the risk of nephrotoxicity and neuromuscular blockade. If coadministration cannot be avoided, monitor renal and neuromuscular function. Risk D: Consider Therapy Modification
Cyclizine: May increase ototoxic effects of Aminoglycosides. Risk C: Monitor
CycloSPORINE (Systemic): Aminoglycosides may increase nephrotoxic effects of CycloSPORINE (Systemic). Risk C: Monitor
Distigmine: Aminoglycosides may decrease therapeutic effects of Distigmine. Risk C: Monitor
Fecal Microbiota (Live) (Oral): May decrease therapeutic effects of Antibiotics. Risk X: Avoid
Fecal Microbiota (Live) (Rectal): Antibiotics may decrease therapeutic effects of Fecal Microbiota (Live) (Rectal). Risk X: Avoid
Foscarnet: May increase nephrotoxic effects of Aminoglycosides. Management: Avoid concomitant use of foscarnet and aminoglycoside antibiotics, unless the expected benefits of combined treatment outweigh the risks. If combined, monitor renal function closely. Risk D: Consider Therapy Modification
Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies): Antibiotics may decrease therapeutic effects of Immune Checkpoint Inhibitors (Anti-PD-1, -PD-L1, and -CTLA4 Therapies). Risk C: Monitor
Loop Diuretics: May increase adverse/toxic effects of Aminoglycosides. Specifically, nephrotoxicity and ototoxicity. Risk C: Monitor
Mannitol (Systemic): May increase nephrotoxic effects of Aminoglycosides. Risk X: Avoid
Mecamylamine: Aminoglycosides may increase neuromuscular-blocking effects of Mecamylamine. Risk X: Avoid
Methotrexate: Neomycin (Systemic) may decrease serum concentration of Methotrexate. Neomycin (Systemic) may increase serum concentration of Methotrexate. Risk C: Monitor
Methoxyflurane: Aminoglycosides may increase nephrotoxic effects of Methoxyflurane. Risk X: Avoid
Mycophenolate: Antibiotics may decrease active metabolite exposure of Mycophenolate. Specifically, concentrations of mycophenolic acid (MPA) may be reduced. Risk C: Monitor
Netilmicin (Ophthalmic): Aminoglycosides may increase nephrotoxic effects of Netilmicin (Ophthalmic). Risk X: Avoid
Neuromuscular-Blocking Agents: Aminoglycosides may increase therapeutic effects of Neuromuscular-Blocking Agents. Risk C: Monitor
Nonsteroidal Anti-Inflammatory Agents: May decrease excretion of Aminoglycosides. Data only in premature infants. Risk C: Monitor
Oxatomide: May increase ototoxic effects of Aminoglycosides. Risk C: Monitor
Penicillins: May decrease serum concentration of Aminoglycosides. Primarily associated with extended spectrum penicillins, and patients with renal dysfunction. Risk C: Monitor
Polymyxin B: May increase nephrotoxic effects of Aminoglycosides. Polymyxin B may increase neurotoxic effects of Aminoglycosides. Risk X: Avoid
Regorafenib: Neomycin (Systemic) may decrease active metabolite exposure of Regorafenib. Risk C: Monitor
Sodium Picosulfate: Antibiotics may decrease therapeutic effects of Sodium Picosulfate. Management: Consider using an alternative product for bowel cleansing prior to a colonoscopy in patients who have recently used or are concurrently using an antibiotic. Risk D: Consider Therapy Modification
SORAfenib: Neomycin (Systemic) may decrease serum concentration of SORAfenib. Risk X: Avoid
Tacrolimus (Systemic): Aminoglycosides may increase nephrotoxic effects of Tacrolimus (Systemic). Risk C: Monitor
Tenofovir Products: Aminoglycosides may increase serum concentration of Tenofovir Products. Tenofovir Products may increase serum concentration of Aminoglycosides. Risk C: Monitor
Typhoid Vaccine: Antibiotics may decrease therapeutic effects of Typhoid Vaccine. Only the live attenuated Ty21a strain is affected. Management: Avoid use of live attenuated typhoid vaccine (Ty21a) in patients being treated with systemic antibacterial agents. Postpone vaccination until 3 days after cessation of antibiotics and avoid starting antibiotics within 3 days of last vaccine dose. Risk D: Consider Therapy Modification
Vancomycin: May increase nephrotoxic effects of Aminoglycosides. Vancomycin may increase neurotoxic effects of Aminoglycosides. Management: Consider avoiding coadministration of aminoglycosides and vancomycin unless clinically indicated. If coadministered, monitor closely for signs of nephrotoxicity and neurotoxicity. Risk D: Consider Therapy Modification
Vitamin K Antagonists: Neomycin (Systemic) may increase anticoagulant effects of Vitamin K Antagonists. Risk C: Monitor
Animal reproduction studies have not been conducted. Aminoglycosides cross the placenta. Aminoglycosides may cause fetal harm if administered to a pregnant woman. There are several reports of total irreversible bilateral congenital deafness in children whose mothers received another aminoglycoside (streptomycin) during pregnancy. Although serious side effects to the fetus/infant have not been reported following maternal use of all aminoglycosides, a potential for harm exists. Large oral doses may cause malabsorption of some nutrients in the mother.
During chronic or high-dose therapy: Renal function tests (serum creatinine, BUN, creatinine clearance); urinalysis (if clinical presentation indicates need); serial vestibular and audiometric tests.
Toxic serum concentrations: ≥1.5 mcg/ml (Marks 1973)
Interferes with bacterial protein synthesis by binding to 30S ribosomal subunits
Absorption: Oral, percutaneous: Poor (3%)
Distribution: 97% of an orally administered dose remains in the GI tract. Absorbed neomycin distributes to tissues and concentrates in the renal cortex. With repeated doses, accumulation also occurs in the inner ear.
Protein binding: 0% to 30%
Time to peak serum concentration: 1 to 4 hours
Excretion: Feces (97% of oral dose as unchanged drug); urine (30% to 50% of absorbed drug as unchanged drug)
