General practitioners' evaluation of side-effects and efficacy of oxamethacin as compared with indomethacin

Distribution of oxametacine and its anti-inflammatory metabolites in inflamed tissues of rats

The anti-inflammatory drug oxametacine (1-p-chlorobenzoyl-5-methoxy-2-methyl-3-indolylacetohydroxamic acid) is extensively metabolized both in laboratory animals and in man. In rats, dosed orally with 5 mg/kg [14C]-oxametacine, there is a 2.2-2.7 fold increase in radioactivity in the inflamed tissues, in the hind-paws of animals with adjuvant arthritis and in the granulomas of cotton-pellet implanted rats. The total tissue radioactivity (following two-fold extraction with methanol; recoveries being 95 +/- 3%) was distributed into the following metabolites: 34-7% oxametacine, 26-37% indomethacin, 16-46% demethylindomethacinamide, and 26-10% indomethacinamide over 2-8 h following drug administration.

Effect of oxametacin on endogenous uric acid clearance rate in healthy volunteers

Oxametacin, a new non steroidal anti-inflammatory compound, with analgesic, antipyretic and anti-inflammatory properties comparable to those of indomethacin, has been claimed to be effective in treatment of acute attacks of gout. The present study comprises an investigation in 8 healthy volunteers of the effect on the endogenous uric acid clearance rate, of oxametacin administered alone or in combination with the conventional hypouricaemic agents benzbromarone or allopurinol. Whether given alone or in combination with these drugs, oxametacin failed to alter the clearance rate of endogenous uric acid. In view of its good tolerance and its possible efficacy in treatment of acute attacks of gout, the present data help to validate use of oxametacin in acute gout.

An analysis of the gastro-intestinal side-effects of non-steroidal anti-inflammatory drugs, with particular reference to comparative studies in man and laboratory species

A critical analysis has been performed of reports published on the incidence of gastro-intestinal (GI) side-effects found in arthritic patients being treated with non-steroid anti-inflammatory (NSAI) drugs. The results show the following: 1. The incidence of GI ulceration (as revealed by gastroscopy) and haemorrhage in arthritic patients taking NSAI drugs may be higher than suspected from clinical trial data. 2. Incidence of all GI side-effects (including ulceration and haemorrhage) may be lower with some of the new NSAI drugs than with traditional drugs (e.g. aspirin, indomethacin and phenylbutazone). 3. Arthritic patients may be more susceptible to the ulcerogenic actions of NSAI drugs. Experiments with animals, together with evidence from clinical studies, indicate that stress factors and the presence of decreased mucosal resistance in the diseased state may contribute to the enhanced susceptibility of the GI tract towards the ulcerogenicity of NSAI drugs. 4. Comparison of data on gastroscopic observations in man with the author's data on the effects of NSAI drugs in stress-sensitized rats shows the latter technique appears to be a useful means of predicting the ulcerogenic potential of NSAI drugs in man. The comparison has also been used to predict the ulcerogenicity of drug - alcohol combinations; alcohol being a common ulcerogen consumed by many patients. Some NSAI drugs with low ulcerogenic activity (i.e. azapropazone, benoxaprofen and fenclofenac) in the stressed-rat assay show little or no interaction with alcohol. These studies using laboratory animals show the importance of employing conditions to mimic environmental factors (e.g. stress and alcohol consumption) which might predispose individuals to ulcerogenic or other side-effects of NSAI drugs. From these studies it appears possible to construct 'predictive profiles' of the relative ulcerogenicity of NSAI drugs which may be applicable to the clinical situation in man.