NSAIDS AND FECAL BLOOD-LOSS IN ELDERLY PATIENTS WITH OSTEOARTHRITIS -IS PLASMA HALF-LIFE RELEVANT

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) vary in thei r degree of gastrointestinal (GI) toxicity. NSAIDs with longer half-li ves are of particular concern as they may be more toxic in the elderly . Aim: To compare the GI toxicity, by measurement of faecal blood loss , of short, intermediate and long half-life NSAID treatments compared with control in elderly patients with osteoarthritis. Methods: Twenty- three patients, mean age 69 years, with osteoarthritis requiring NSAID treatment, received treatment with diclofenac 100 mg/day, naproxen 75 0 mg/day and piroxicam 20 mg/day, representing a short, medium and lon g half-life NSAID respectively, in a double-blind, randomised, three w ay, cross-over block design. In each case, a three week washout contro l phase was followed by active treatment phases of two weeks each with three week washout between treatment phases. Results: Faecal blood lo ss, collected over 72 hours at the end of each treatment phase, was me asured by Cr-51-labelled erythrocyte method. Comparison was made of me an 24 hour faecal blood loss with each treatment compared with control using repeated measures analysis of variance. Eighteen patients compl eted all phases of the study. Three patients were withdrawn due to GI bleeding; two during diclofenac treatment and one during treatment wit h piroxicam. Mean 24 hour faecal blood loss with diclofenac (0.53 mL /- 0.21) was not significantly different from control (0.28 mL +/- 0.0 6), whereas it was significantly increased with naproxen (2.76 mL +/- 2.22) and piroxicam (1.16 mL +/- 0.62), p = 0.0013. Conclusion: A shor t half-life NSAID was associated with lower GI toxicity than a medium and long half-life NSAID, as measured by faecal blood loss.