NEOMYCIN SULFATE- neomycin sulfate tablet
Breckenridge Pharmaceutical, Inc.
To reduce the development of drug-resistant bacteria and maintain the effectiveness of Neomycin Sulfate Tablets USP and other antibacterial drugs. Neomycin Sulfate Tablets USP should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.
WARNINGS: 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 their use. NEUOROTOXICITY (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 BILATREAL AUDITORY OTOTOXICITY AND SOMETIMES VESTIBULAR TOXICITY IS PRESENT IN PATIENTS WITH NORMAL RENAL FUNCTION WHEN TREATED WITH HIGHER DOSES OF NEOMYCIN AND/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
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 in patients receiving massive transfusions of citrate anticoagulated blood. If blockage occurs, calcium salts may reverse these phenomena but mechanical respiratory assistance may be necessary.
Concurrent and/or sequential systemic, oral or topical use of other aminoglycosides, including paromomycin and other potentially nephrotoxic and/or neurotoxic drugs such as bacitracin, cisplatin, vancomycin, amphotericin B, polymyxin B, colistin and viomycin, should be avoided because the toxicity may be additive.
Other factors which increase the risk of toxicity are advanced age and dehydration. 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, diuretics may enhance neomycin toxicity by altering the antibiotic concentration in serum and tissue.
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:
Chemically, it is O -2,6-diamino-2,6-dideoxy-α-D-glucopyranosyl-(1→ 3)-O -β-D-ribofuranosyl-(1→5)-O -[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.
Each tablet contains 500 mg Neomycin Sulfate (equivalent to 350 mg neomycin base).
Inactive Ingredients: Calcium Stearate, Colloidal Silicon Dioxide, 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 concentrations 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 mcg 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 USP and other antibacterial drugs, Neomycin Sulfate Tablets USP 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, e.g., 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.
Patients with a history of hypersensitivity or serious toxic reaction 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.
Prescribing Neomycin Sulfate Tablets USP in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide beneﬁt to the patient and increases the risk of the development of drug-resistant bacteria.
As with other antibiotics, use of oral neomycin may result in overgrowth of non-susceptible organisms, particularly fungi. If this occurs, appropriate therapy should be instituted.
Neomycin is quickly and almost totally absorbed from body surfaces (except the urinary bladder) after local irrigation and when applied topically in association with surgical procedures. Delayed-onset irreversible deafness, renal failure and death due to neuromuscular blockade (regardless of the status of renal function) have been reported following irrigation of both small and large surgical ﬁelds with minute quantities of neomycin.
Cross-allergenicity among aminoglycosides has been demonstrated.
Aminoglycosides should be used with caution in patients with muscular disorders such as myasthenia gravis or parkinsonism since these drugs may aggravate muscle weakness because of their potential curare-like effect on the neuromuscular junction.
Small amounts of orally administered neomycin are absorbed through intact intestinal mucosa.
There have been many reports in the literature of nephrotoxicity and/or ototoxicity with the oral use of neomycin. If renal insufﬁciency develops during oral therapy, consideration should be given to reducing the drug dosage or discontinuing therapy.
An oral neomycin dose of 12 grams per day produces a malabsorption syndrome for a variety of substances, including fat, nitrogen, cholesterol, carotene, glucose, xylose, lactose, sodium, calcium, cyanocobalamin and iron.
Orally administered neomycin increases fecal bile acid excretion and reduces intestinal lactase activity.
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