Neomycin Sulfate Tablets, USP, for oral administration, contain neomycin which is an antibiotic obtained from the metabolic products of the actinomycete Streptomyces fradiae. Structurally, neomycin sulfate may be represented as follows:

molecular structure

Chemically, it is 0-2, 6-diamino-2, 6-dideoxy-α-D-glucopyranosyl-(1→3)-0-β-D-ribofuranosyl- (1→5)-0-[2,6-diamino-2, 6-dideoxy-α-D-glucopyranosyl -(1→4)]-2-deoxy-D-streptamine. Neomycin B is identical except that the α-D-glucopyranosyl residue in the neobiosamine moiety is β-L-idopyranosyl.

InactiveIngredients: Calcium Stearate, Povidone.

Neomycin sulfate is poorly absorbed from the normal gastrointestinal tract. The small absorbed fraction is rapidly distributed in the tissues and is excreted by the kidney in keeping with the degree of kidney function. The unabsorbed portion of the drug (approximately 97%) is eliminated unchanged in the feces.

Growth of most intestinal bacteria is rapidly suppressed following oral administration of neomycin sulfate, with the suppression persisting for 48 to 72 hours. Nonpathogenic yeasts and occasionally resistant strains of Enterobacter aerogenes (formerly Aerobacter aerogenes) replace the intestinal bacteria.

As with other aminoglycosides, the amount of systemically absorbed neomycin transferred to the tissues increases cumulatively with each repeated dose administered until a steady state is achieved. The kidney functions as the primary excretory path as well as the tissue binding site, with the highest concentration found in the renal cortex. With repeated dosings, progressive accumulation also occurs in the inner ear. Release of tissue-bound neomycin occurs slowly over a period of several weeks after dosing has been discontinued.

Protein binding studies have shown that the degree of aminoglycoside protein binding is low and, depending upon the methods used for testing, this may be between 0% and 30%.

Microbiology: In vitro tests have demonstrated that neomycin is bactericidal and acts by inhibiting the synthesis of protein in susceptible bacterial cells. It is effective primarily against gram-negative bacilli but does have some activity against gram-positive organisms. Neomycin is active in vitro against Escherichia coli and the Klebsiella-Enterobacter group. Neomycin is not active against anaerobic bowel flora.

If susceptibility testing is needed, using a 30 msg disc, organisms producing zones of 16 mm or greater are considered susceptible. Resistant organisms produce zones of 13 mm or less. Zones greater than 13 mm and less than 16 mm indicate intermediate susceptibility.

To reduce the development of drug-resistant bacteria and maintain the effectiveness of neomycin sulfate tablets and other antibacterial drugs, neomycin sulfate tablets should be used only to treat or prevent infections that are proven or strongly suspected to be caused by susceptible bacteria. When culture and susceptibility information are available, they should be considered in selecting or modifying antibacterial therapy. In the absence of such data, local epidemiology and susceptibility patterns may contribute to the empiric selection of therapy.

Suppression of intestinal bacteria: Neomycin sulfate tablets are indicated as adjunctive therapy as part of a regimen for the suppression of the normal bacterial flora of the bowel, eg, preoperative preparation of the bowel. It is given concomitantly with erythromycin enteric-coated base (see DOSAGE AND ADMINISTRATION section).

Hepatic coma (portal-systemic encephalopathy): Neomycin sulfate has been shown to be effective adjunctive therapy in hepatic coma by reduction of the ammonia-forming bacteria in the intestinal tract. The subsequent reduction in blood ammonia has resulted in neurologic improvement.

Neomycin sulfate oral preparations are contraindicated in the presence of intestinal obstruction and in individuals with a history of hypersensitivity to the drug.

Patients with a history of hypersensitivity or serious toxic reaction to other aminoglycosides may have a cross-sensitivity to neomycin.

Neomycin sulfate oral preparations are contraindicated in patients with inflammatory or ulcerative gastrointestinal disease because of the potential for enhanced gastrointestinal absorption of neomycin.

(see boxed WARNINGS): Additional manifestations of neurotoxicity may include numbness, skin tingling, muscle twitching and convulsions.

The risk of hearing loss continues after drug withdrawal.

Aminoglycosides can cause fetal harm when administered to a pregnant woman. Aminoglycoside antibiotics cross the placenta and there have been several reports of total irreversible bilateral congenital deafness in children whose mothers received streptomycin during pregnancy. Although serious side effects to fetus or newborn have not been reported in the treatment of pregnant women with other aminoglycosides, the potential for harm exists. Animal reproduction studies of neomycin have not been conducted. If neomycin is used during pregnancy, or if the patient becomes pregnant while taking this drug, the patient should be apprised of the potential hazard to the fetus.

The most common adverse reactions to oral neomycin sulfate are nausea, vomiting and diarrhea. The "Malabsorption Syndrome" characterized by increased fecal fat, decreased serum carotene and fall in xylose absorption has been reported with prolonged therapy. Nephrotoxicity, ototoxicity and neuromuscular blockage have been reported (see boxed WARNINGS and PRECAUTIONS sections).

Because of low absorption, it is unlikely that acute overdosage would occur with oral neomycin sulfate. However, prolonged administration could result in sufficient systemic drug levels to produce neurotoxicity, ototoxicity and/or nephrotoxicity.

Hemodialysis will remove neomycin sulfate from the blood.

To minimize the risk of toxicity, use the lowest possible dose and the shortest possible treatment period to control the condition. Treatment for periods longer than two weeks is not recommended.

Hepatic coma: For use as an adjunct in the management of hepatic coma, the recommended dose is 4 to 12 grams per day given in the following regimen:

1. Withdraw protein from diet.  Avoid use of diuretic agents.
2. Give supportive therapy, including blood products, as indicated.
3. Give Neomycin Sulfate Tablets in doses of 4 to 12 grams of neomycin sulfate per day (eight to 24 tablets) in divided doses. Treatment should be continued over a period of five to six days, during which time protein should be returned incrementally to the diet.
4. If less potentially toxic drugs cannot be used for chronic hepatic insufficiency, neomycin in doses of up to four grams daily (eight tablets per day) may be necessary. The risk for the development of neomycin-induced toxicity progressively increases when treatment must be extended to preserve the life of a patient with hepatic encephalopathy who has failed to fully respond.  Frequent periodic monitoring of these patients to ascertain the presence of drug toxicity is mandatory (see PRECAUTIONS). Also, neomycin serum concentrations should be monitored to avoid potentially toxic levels. The benefits to the patient should be weighed against the risks of nephrotoxicity, permanent ototoxicity and neuromuscular blockade following the accumulation of neomycin in the tissues.

Neomycin Sulfate Tablets, USP, 500 mg (equivalent to 350 mg of neomycin base per tablet) are available as round, off-white, unscored tablets, debossed "500" and "PT".  Supplied as: NDC 39822-0310-5 as Unit dose blister packages of 100 tablets (10 strips of 10 tablets each).  Store at 20º to 25ºC (68º to 77ºF) [see USP Controlled Room Temperature].

Dispense in tight containers as defined in the USP/NF.

Manufactured in Canada

Manufactured for:

X-Gen Pharmaceuticals, Inc.

Big Flats, NY 14814

Revised November, 2010

NDC 39822-310-5
Neomycin Sulfate Tablets, USP
500 mg; Each tablet contains:

Neomycin Sulfate 500 mg equivalent in activity to 0.35 g Neomycin base per tablet.

Rx Only
1 Carton of 100 Tablets
X-GEN Pharmaceuticals, Inc.

unit dose label

NST-CA-01