Azulfidine EN Tablets and Renal dysfunction

Sulfonamides and their metabolites are eliminated by the kidney. Patients with renal impairment may be at greater risk for adverse effects from sulfonamides due to decreased drug clearance. Dosage adjustments may be necessary and modifications should be based on the degree of renal impairment and severity of infection. Additionally, sulfonamides may cause renal toxicity secondary to crystalluria, including uro- and nephrolithiasis, nephritis, toxic nephrosis, hematuria, proteinuria, and elevated BUN and creatinine. Hydration (8 oz. glass of water with each dose and throughout the day) and adequate urinary output (> 1.5 L/day) should be maintained during sulfonamide administration. Renal function tests and urinalysis should be performed weekly or as often as indicated by the patient's status. Rarely, alkalinization of the urine is necessary.

The use of mesalamine and other compounds which contain or are converted to mesalamine has rarely been associated with renal adverse effects, including minimal change nephropathy, acute and chronic interstitial nephritis, and nephrogenic diabetes insipidus. Renal lesions such as renal infarct, papillary necrosis, tubular necrosis and interstitial fibrosis have been reported in high-dose animal studies. Therapy with mesalamine and prodrugs of mesalamine should be administered cautiously in patients with impaired renal function or a history of renal disease. Renal function should be evaluated prior to initiation of therapy and periodically during therapy.