Urinary glucaric acid excretion in rheumatoid arthritis: influence of disease activity and disease modifying drugs.

Abstract

Objective-To examine if a correlation exists between cytochrome P-450 enzyme induction and disease activity in patients with rheumatoid arthritis (RA), measuring urinary excretion of D-glucaric acid (GA) as an index ofphase II drug metabolism. States of inflammation also may affect the rate of drug metabolism. In man, it has been shown that fever induced by the steroid pyrogen etiocholanolone or injected endotoxin is followed by impaired hydroxylation of antipyrine, conjugation of bromosulphthalein, and glucuronidation of salicylamide. Acute viral infections and influenza vaccination can impair cytochrome P-450 dependent oxidative drug metabolism leading to toxicity of theophylline, phenytoin, and warfarin. In animal models with adjuvant arthritis, a marked impairment of drug metabolism in vitro and in vivo has been shown.35