Measurement of renal functions by double isotope techniques in elderly patients during tenoxicam therapy.

Four elderly patients (aged 68-87 yr) with osteoarthritis were treated with 20 mg of tenoxicam (a new non-steroidal anti-inflammatory drug) daily for at least 12 weeks. Tenoxicam did not appear to have any harmful effect on glomerular filtration rate and effective renal plasma flow, as measured by a single intravenous injection of 51Cr-EDTA and 125I-iodohippurate. Plasma concentration of tenoxicam indicated good compliance, and no evidence of unexpected accumulation of tenoxicam in the plasma was observed during 12 weeks of medication.