Neomycin Sulfate

Neomycin Sulfate is an antibiotic used to reduce the risk of infection during surgery of the bowel. Neomycin is also used to reduce the symptoms of hepatic coma. Neomycin sulfate is available in generic form.

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.

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 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 highrisk 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.

Common side effects of neomycin sulfate include:

• nausea,
• vomiting, or
• diarrhea.

Contact your doctor if you have serious side effects of neomycin including:

• drowsiness,
• confusion,
• mood changes,
• increased thirst,
• loss of appetite,
• weight gain,
• shortness of breath,
• shallow breathing,
• hearing problems,
• spinning sensation,
• feeling like you might pass out,
• loss of balance or coordination,
• trouble walking,
• numbness or tingly feeling under your skin,
• muscle twitching,
• seizures (convulsions),
• urinating less than usual or not at all,
• swelling,
• severe stomach cramps, or
• diarrhea that is watery or bloody.

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 4-12 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 4-12 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. 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.

Preoperative Prophylaxis For Elective Colorectal Surgery

Listed below is an example of a recommended bowel preparation regimen. A proposed surgery time of 8:00 a.m. has been used.

• Pre-op Day 3: Minimum residue or clear liquid diet. Bisacodyl, 1 tablet orally at 6:00 p.m.
• Pre-op Day 2: Minimum residue or clear liquid diet. Magnesium sulfate, 30 mL, 50% solution (15 g) orally at 10:00 a.m., 2:00 p.m., and 6:00 p.m. Enema at 7:00 p.m. and 8:00 p.m.
• Pre-op Day 1: Clear liquid diet. Supplemental (IV) fluids as needed. Magnesium sulfate, 30 mL, 50% solution (15 g) orally at 10:00 a.m. and 2:00 p.m. Neomycin sulfate (1 g) and erythromycin base (1 g) orally at 1:00 p.m., 2:00 p.m. and 11:00 p.m. No enema

Day of Operation: Patient evacuates rectum at 6:30 a.m. for scheduled operation at 8:00 a.m.

• Caution should be taken in concurrent or serial use of other neurotoxic and/or nephrtoxic drugs because of possible enhancement of the nephrotoxicity and/or ototoxicity of neomycin.
• Caution should also be taken in concurrent or serial use of other aminoglycosides and polymyxins because they may enhance neomycin's nephrotoxicity and/or ototoxicity and potentiate neomycin sulfate's neuromuscular blocking effects.
• Oral neomycin inhibits the gastrointestinal absorption of penicillin V, oral vitamin B-12, methotrexate and 5-fluorouracil. The gastrointestinal absorption of digoxin also appears to be inhibited. Therefore, digoxin serum levels should be monitored.
• Oral neomycin sulfate may enhance the effect of coumarin in anticoagulants by decreasing vitamin K availability.

• 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.
• It is not known whether neomycin is excreted in human milk, but it has been shown to be excreted in cow milk following a single intramuscular injection.
•  Other aminoglycosides have been shown to be excreted in human milk.
• Because of the potential for serious adverse reactions from the aminoglycosides in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.