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Neomycin Sulfate


Pronunciation: NEE-oh-MY-sin SULL-fate
Class: Aminoglycoside

Trade Names

Neomycin Sulfate
- Tablets 500 mg

- Oral solution 125 mg per 5 mL


Inhibits production of protein in bacteria, causing bacterial cell death.

Slideshow: View Frightful (But Dead Serious) Drug Side Effects



Poorly absorbed from the GI tract (3%).


Small amount absorbed is rapidly distributed to the tissues. Removed by dialysis.


Small fraction absorbed is eliminated by the kidney. The unabsorbed portion (97%) is eliminated unchanged in the feces.

Indications and Usage

As adjunctive treatment for suppression of normal bacterial flora of the bowel (tablet); as adjunctive therapy in hepatic coma to reduce ammonia-forming bacteria in the intestinal tract (tablet and solution).


Patients with intestinal obstruction; inflammatory or ulcerative GI disease; history of sensitivity to aminoglycosides or any component of the product.

Dosage and Administration

Hepatic Coma

PO 4 to 12 g/day in divided doses. Treatment should be continued over a period of 5 to 6 days.

Preoperative Prophylaxis

PO As part of a bowel preparation regimen, 1 g of neomycin and 1 g of erythromycin are given orally on pre-op day 1 at 1 PM, 2 PM, and 11 PM.

General Advice

  • Administer without regard to meals. Administer with food if GI upset occurs.


Store tablets at controlled room temperature (68° to 77°F). Store oral solution at controlled room temperature (59° to 86°F).

Drug Interactions

Aminoglycosides, polymyxins, neurotoxic or nephrotoxic agents

Neomycin ototoxicity or nephrotoxicity may be enhanced.

Anticoagulants (eg, warfarin)

May increase the anticoagulant effects by decreasing vitamin K availability.

Digoxin, fluorouracil, methotrexate, penicillin V, vitamin B-12

Intestinal absorption of these agents may be inhibited by neomycin.

Potent diuretics (eg, ethacrynic acid, furosemide)

When administered IV, diuretics may enhance neomycin toxicity by altering the concentration in serum and tissue.

Laboratory Test Interactions

None well documented.

Adverse Reactions




Nausea; vomiting; diarrhea.




Malabsorption syndrome.


Neuromuscular blockade.



Systemic absorption of neomycin occurs after oral administration, and toxic reactions may occur (eg, ototoxicity, nephrotoxicity). Neuromuscular blockade and respiratory paralysis have been reported. The risk of toxicity may be increased by dehydration or advanced age.


Category D .




Safety and efficacy not established.

Renal Function

If renal insufficiency develops during oral therapy, consider reducing the neomycin dose or discontinuing therapy.

Special Risk Patients

Use with caution in patients with muscular disorders (eg, myasthenia gravis, parkinsonism) because neomycin may aggravate muscle weakness.


Prolonged or repeated use may result in bacterial or fungal overgrowth of nonsusceptible organisms and secondary infections.

Bile acid

Bile acid fecal excretion may be increased.

Hearing loss

Risk may continue after drug withdrawal.


Intestinal lactase activity may be reduced.

Malabsorption syndrome

Oral neomycin (12 g/day) produces malabsorption of a variety of substances including fat, nitrogen, cholesterol, carotene, glucose, xylose, lactose, sodium, calcium, cyanocobalamin, and iron.



Neurotoxicity, ototoxicity, nephrotoxicity.

Patient Information

  • Review dosing schedule and prescribed length of therapy with patient.
  • Advise patient to take each dose without regard to meals but to take with food if stomach upset occurs.
  • Remind patient to complete entire course of therapy.
  • Caution patient not to change the dose or discontinue therapy unless advised by health care provider.
  • Warn patient that diarrhea containing blood or pus may be a sign of a serious disorder and to seek medical care if noted and not treat at home.
  • Advise patient to contact health care provider immediately if experiencing ringing in the ears, hearing loss, vestibular symptoms (eg, dizziness, incoordination), severe diarrhea, muscle twitching, numbness, skin tingling, or loose, foul-smelling stools.

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