An assessment of tenoxicam, a nonsteroidal anti-inflammatory drug of long half-life, in patients with impaired renal function suffering from osteoarthritis or rheumatoid arthritis.

Fifty-eight patients, aged 48-87 years, with impaired renal function and mean initial creatinine clearance of 52.1 mls/min were recruited to a 12-week open study of tenoxicam 20 mg/day for osteoarthrosis or rheumatoid arthritis. Renal function was measured before and after a brief run-in period when patients discontinued all nonsteroidal anti-inflammatory drugs, taking paracetamol alone, prior to monthly monitoring thereafter. Fifty-four % of patients completed the study, the others being withdrawn from lack of efficacy (17%), adverse events (24%) or both (5%). During the run-in period the mean creatinine clearance of 28 patients completing the trial improved to 64.7 mls/min and then dropped to 57.9 mls/min during the course of 12 weeks treatment with tenoxicam. Serial analysis of haematological and biochemical safety parameters showed no drug-induced change of significance. Twenty-three% of patients felt worse and 45% better at the end of treatment. Seventeen patients withdrew because of adverse events. These were normally gastrointestinal and always unrelated to further deterioration in renal function. Tenoxicam, 20 mg/day, can be given safely for a period of at least three months in patients with mild or moderate renal impairment.