Importance of local versus systemic effects of non-steroidal anti-inflammatory drugs in increasing small intestinal permeability in man

Increased small intestinal permeability caused by non-steroidal anti-inflammatory drugs (NSAIDs) is probably a prerequisite for NSAID enteropathy, a source of morbidity in patients with rheumatoid arthritis. This increased small intestinal permeability may be a summation of a local effect during drug absorption, a systemic effect after absorption, and a local effect of the drug excreted in bile, but the relative contribution made by these factors is unknown. We assessed the effect of indomethacin and nabumetone on intestinal permeability. The principal active metabolite of nabumetone, 6-methoxy-2-naphthylacetic acid, is not subject to appreciable enterohepatic recirculation. Twelve volunteers were studied before and after one week's ingestion of indomethacin (150 mg/day) and nabumetone (1 g/day) with a combined absorption/permeability test. Neither drug had a significant effect on the permeation of 3-0-methyl-D-glucose, D-xylose, and L-rhamnose. Indomethacin increased the permeation of radioactive 51chromium ethylenediaminetetra-acetic acid (51Cr EDTA) significantly from baseline (mean (SEM) 0.63 (0.09)% v 1.20 (0.14)%, p less than 0.01) but nabumetone did not (0.70 (0.10)% p greater than 0.1). These results were supported by the 51Cr EDTA/L-rhamnose urine excretion ratios, which reflect changes in intestinal permeability. They suggest that NSAIDs increase intestinal permeability during absorption or after biliary excretion and that the systemic effect is of minor importance.

A microcomputer-assisted study of nabumetone and slow release diclofenac in osteoarthritis

20 UK general-practice centres entered 243 patients into a 6-week double-blind, double-dummy, randomised, parallel-group trial designed to compare nabumetone 1 g at night with slow release diclofenac 100mg at night in the treatment of osteoarthritis. Seven efficacy parameters were measured, adverse events were recorded and laboratory monitoring was performed. The study monitor entered trial data into a portable laptop microcomputer at the participating centres. Both treatment groups showed highly significant clinical improvements at the end of the 6-week study period and there were no significant inter-group differences. Overall, the incidence of adverse events was similar in the 2 groups, but significantly fewer patients in the nabumetone group (n = 21) than in the diclofenac group (n = 35) complained of gastrointestinal adverse events (p = 0.03). On-site use of the microcomputer contributed to increased monitoring efficiency and trialist motivation, resulting in rapid recruitment of patients, collection of high quality data and speedy analysis at the end of the study.