PRECAUTIONS General Audiometric measurements and assessment of vestibular function should be performed prior to initiation of therapy with Capastat Sulfate and at regular intervals during treatment. Renal injury, with tubular necrosis, elevation of the blood urea nitrogen (BUN) or serum creatinine, and abnormal urinary sediment, has been noted. Slight elevation of the BUN and serum creatinine has been observed in a significant number of patients receiving prolonged therapy. The appearance of casts, red cells, and white cells in the urine has been noted in a high percentage of these cases. Elevation of the BUN above 30 mg/100 mL or any other evidence of decreasing renal function with or without a rise in BUN levels calls for careful evaluation of the patient, and the dosage should be reduced or the drug completely withdrawn. The clinical significance of abnormal urine sediment and slight elevation in the BUN (or serum creatinine) observed during long-term therapy with Capastat Sulfate has not been established. The peripheral neuromuscular blocking action that has been attributed to other polypeptide antibiotics (colistin sulfate, polymyxin A sulfate, paromomycin, and viomycin) and to aminoglycoside antibiotics (streptomycin, dihydrostreptomycin, neomycin, and kanamycin) has been studied with Capastat Sulfate. A partial neuromuscular blockade was demonstrated after large intravenous doses of Capastat Sulfate. This action was enhanced by ether anesthesia (as has been reported for neomycin) and was antagonized by neostigmine. Caution should be exercised in the administration of antibiotics, including Capastat Sulfate, to any patient who has demonstrated some form of allergy, particularly to drugs. Laboratory Tests Regular tests of renal function should be made throughout the period of treatment, and reduced dosage should be employed in patients with known or suspected renal impairment. Renal function studies should be made both before therapy with Capastat Sulfate is started and on a weekly basis during treatment. Since hypokalemia, hypomagnesemia and hypocalcemia may occur during therapy, these serum electrolyte levels should be determined frequently. Drug Interactions For neuromuscular blocking action of this drug, see PRECAUTIONS, GENERAL. Carcinogenesis, Mutagenesis, Impairment of Fertility Studies have not been performed to determine potential for carcinogenicity, mutagenicity, or impairment of fertility. Usage in Pregnancy Capastat Sulfate has been shown to be teratogenic in rats when given in doses 3 1/2 times the human dose. There are no adequate and well-controlled studies in pregnant women. Capastat Sulfate should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus (see boxed WARNINGS and ANIMAL PHARMACOLOGY). Nursing Mothers It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when Capastat Sulfate is administered to a nursing woman. Pediatric Use Safety and effectiveness in pediatric patients have not been established (see boxed WARNINGS). Geriatric Use Clinical studies of Capastat Sulfate did not analyze the safety and efficacy of patients aged 65 and over to determine whether they respond differently from younger patients. Other reported clinical experience has not identified differences in responses between the elderly and younger patients. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy. Capastat Sulfate is known to be substantially excreted by the kidney (see CLINICAL PHARMACOLOGY), and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and it may be useful to monitor renal function (see PRECAUTIONS, Laboratory Tests). Patients with reduced renal function should have dosage reduction based on creatinine clearance using the guidelines included in Table 1 (see DOSAGE AND ADMINISTRATION). The geriatric population is also more likely to have impaired hearing at baseline. Audiometric measurements and assessment of vestibular function should be performed prior to initiation of therapy with Capastat Sulfate and at regular intervals during treatment (see PRECAUTIONS, General).