NEOMYCIN Drug Interactions: What You Need to Know

Drug Interactions Caution should be taken in concurrent or serial use of other neurotoxic and/or nephrotoxic drugs because of possible enhancement of the nephrotoxicity and/or ototoxicity of neomycin (see boxed WARNINGS ) . 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.

CONTRAINDICATIONS 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 gastro- intestinal disease because of the potential for enhanced gastrointestinal absorption of neomycin.

WARNINGS PROPHYLACTIC BLADDER CARE WITH NEOMYCIN AND POLYMYXIN B SULFATES SOLUTION FOR IRRIGATION SHOULD NOT BE GIVEN WHERE THERE IS A POSSIBILITY OF SYSTEMIC ABSORPTION. NEOMYCIN AND POLYMYXIN B SULFATES SOLUTION SHOULD NOT BE USED FOR IRRIGATION OTHER THAN FOR THE URINARY BLADDER. Systemic absorption after topical application of neomycin to open wounds, burns, and granulating surfaces is significant and serum concentrations comparable to and often higher than those attained following oral and parenteral therapy have been reported. Absorption of neomycin from the denuded bladder surface has been reported. However, the likelihood of toxicity following topical irrigation of the intact urinary bladder with Neomycin and Polymyxin B Sulfates Solution for Irrigation is low since no appreciable amounts of these antibiotics enter the systemic circulation by this route if irrigation does not exceed 10 days. Neomycin and Polymyxin B Sulfates Solution for Irrigation is intended for continuous prophylactic irrigation of the lumen of the intact urinary bladder of patients with indwelling catheters. Patients should be under constant supervision by a physician. Irrigation should be avoided in patients with defects in the bladder mucosa or bladder wall, such as vesical rupture, or in association with operative procedures on the bladder wall, because of the risk of toxicity due to systemic absorption following diffusion into absorptive tissues and spaces. When absorbed, neomycin and polymyxin B are nephrotoxic antibiotics, and the nephrotoxic potentials are additive. In addition, both antibiotics, when absorbed, are neurotoxins: neomycin can destroy fibers of the acoustic nerve causing permanent bilateral deafness; neomycin and polymyxin B are additive in their neuromuscular blocking effects, not only in terms of potency and duration, but also in terms of characteristics of the blocks produced. Aminoglycosides, when absorbed, 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 have not been reported in the treatment of pregnant women with other aminoglycosides, the potential for harm exists.

If

Neomycin and Polymyxin B Sulfates Solution for Irrigation is used during pregnancy, the patient should be apprised of the potential hazard to the fetus (see PRECAUTIONS ).