Nephrotoxicity neomycin

These dm are contraindicated in patients with known hypersensitivity to the drug or any components of the drug. Because neomycin toxicity can cause nephrotoxicity and ototoxicity, neomycin is used cautiously in patients with extensive bums or trophic ulceration when extensive absorption can occur. 

Antibiotics with activity against urease-producing bacteria, such as neomycin [42], paromomycin [44] or metronidazole [45], also reduce the production of intestinal ammonia and have proved to be of value. Vancomycin has also been used in patients with lactulose-resistant chronic encephalopathy [46]. The efficacy of neomycin is similar to that of lactulose [42]. However, a small percentage of this drug is absorbed from the gastrointestinal tract and may cause ototoxic and nephrotoxic effects, especially with continuous use over several months [47]. This drug should be used with particular caution by patients with renal insufficiency. The efficacy of metronidazole for... 

Neomycin is commonly used in combination with other drugs. Pa-renterally, neomycin is quite nephrotoxic. It is most often used topically in animals with infectious diseases of the eye and external ear or contaminated wounds. Neomycin is also available alone or in combination with other drugs for the treatment of enteric infections and for the intra-mammary treatment of mastitis in cows. 

Nausea, vomiting, diarrhea (most common) malabsorption syndrome characterized by increased fecal fat, decreased serum carotene, and fall in xylose absorption. Clostridium difficile-assoaated colitis (following neomycin therapy) nephrotoxicity and ototoxicity (following prolonged and high-dosage therapy in hepatic coma). 

Avoid concurrent or sequential use of other neurotoxic and/or nephrotoxic drugs with streptomycin sulfate, including neomycin, kanamycin, gentamicin, cephaloridine, paromomycin, viomycin, polymyxin B, colistin, tobramycin, and cyclosporine. 

Bacitracin is highly nephrotoxic when administered systemically and is only used topically (Chapter 62). Bacitracin is poorly absorbed. Topical application results in local antibacterial activity without systemic toxicity. Bacitracin, 500 units/g in an ointment base (often combined with polymyxin or neomycin), is indicated for the suppression of mixed bacterial flora in surface lesions of the skin, in wounds, or on mucous membranes. Solutions of bacitracin containing 100-200 units/mL in saline can be used for irrigation of joints, wounds, or the pleural cavity. 

All members of the neomycin group have significant nephrotoxicity and ototoxicity. Auditory function is affected more than vestibular function. Deafness has occurred, especially in adults with impaired renal function and prolonged elevation of drug levels. 

Neomycin is administered orally for treatment of bacterial infections of cattle, sheep, pigs, goats, and poultry at a dosage of 10 mg/kg bw. It is also used as a feed additive for growth-promoting purposes. Neomycin is further available alone or in combination with other drugs such as oxytetracycline, oleandomycin, lincomycin, and prednisolone, in intramammary formulations for treatment of mastitis. There has been relatively little clinical use of neomycin parenterally in animals because of the compound s reported nephrotoxicity and ototoxicity. 

Neomycin is particularly ototoxic and nephrotoxic when given parenterally. As with gentamicin and kanamycin, the nephrotoxicity may be reversible but the ototoxicity is usually irreversible and deafness may occur following oral administration, instillation into cavities, or topical use. It may block neuromuscular action and respiratory depression has been reported. Local treatments may cause hypersensitivity, rashes, pruritus, and anaphylaxis. Neomycin is not geno-toxic. 

Polymyxin B is effective against many gramnegative bacteria, including E. coli, Klebsiella, and Salmonella. Systemic administration of this drug, however, is often associated with extreme nephrotoxicity. Hence, this agent is used primarily for the treatment of local, superficial infections of the skin, eyes, and mucous membranes. When applied topically for these conditions, adverse reactions are relatively rare. Polymyxin B is often combined with other antibiotics such as bacitracin and neomycin in commercial topical preparations. 

Topical application of neomycin rarely results in detectable serum concentrations. However, in the case of gentamicin, serum concentrations of 1-18 g/mL are possible if the drug is applied in a water-miscible preparation to large areas of denuded skin, as in burned patients. Both drugs are water-soluble and are excreted primarily in the urine. Renal failure may permit the accumulation of these antibiotics, with possible nephrotoxicity, neurotoxicity, and ototoxicity. 

Administration The highly polar, polycationic structure of the aminoglycosides prevents adequate absorption after oral administration. Therefore, all aminoglycosides (except neomycin [nee oh MYE sin]) must be given parenterally to achieve adequate serum levels. [Note The severe nephrotoxicity associated with neomycin precludes parenteral administration, and its current use is limited to topical application or oral treatment in hepatic coma to reduce the intestinal bacterial population.]... 

Distribution All of the aminoglycosides have similar pharmacokinetic properties. Levels achieved in most tissues are low, and penetration into most body fluids is variable. Concentrations in cerebrospinal fluid are inadequate even when the meninges are inflamed. Except for neomycin, the aminoglycosides may be administered intrathecally. High concentrations accumulate in the renal cortex and in the endolymph and perilymph of the inner ear, which may account for their nephrotoxic and ototoxic potential. All cross the placental barrier and may accumulate in fetal plasma and amniotic fluid. 

Neomycin (4 g daily in divided doses) is a non-absorbable antibiotic which may be used to reduce the number of bacteria in the bowel that normally break down protein. Neomycin therapy is usually limited to one week s therapy because some absorption may occur with a risk of nephrotoxicity and ototoxicity. 

The same spectrum of toxicity (ototoxicity and nephrotoxicity) is shared by all members of the group, The more important and frequent interactions are pharmacodynamic. Streptomycin and gentamicin produce predominantly vestibular effects, whereas amikacin, kanamycin and neomycin primarily affect auditory function. All are rapidly excreted by the kidney,... 

Experimental exposiue of neomycin in calves has reported both nephrotoxicity and ototocity (demonstrated clinically). The clinical pathological observations included granular casts in urine, proteinuria and low specific gravity, azotemia, decreased creatinine clearance, polyuria, and polydipsia. The histopathological findings included renal tubular epithelial degeneration and necrosis (Crowell et al, 1981). 

Neomycin is not usually administered parenter-ally to animals because of nephrotoxicity and ototoxicity. Only 3% of a dose of neomycin is absorbed following p.o. administration it is, therefore, used in the therapy of coliform enteritis in small and large animals. It is available as tablets, boluses and water additives, in many different combinations with antibiotics, corticosteroids and anticholinergic agents. It can also be used to decrease nitrogenous waste production by the normal gastrointestinal flora in animals with hepatic encephalopathy. Neomycin is not absorbed through the skin, so it is frequently utilized as the antibacterial constituent in ophthalmic formulations (especially in combination with bacitracin and polymyxin B) and in preparations for the treatment of otitis externa in small animals. 

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