Effect of propyphenazone on drug biotransformation in the liver. A comparison with phenylbutazone using the aminopyrine breath test

: By means of the aminopyrine breath analysis the influence of phenylbutazone, propyphenazone and of the combination preparation Wofapyrin "new" on the aminopyrine-N-demethylation, a hepatic microsomal performance of biotransformation in patients with diseases of the rheumatic circle of forms was examined. The enzyme-inducing effect of phenylbutazone known from literature could be confirmed. On the other hand despite a relatively highly dosed one-week treatment propyphenazone did not lead to changes of the demethylation capacity of the liver in the majority of the patients. In individual cases increases of the capacity are possible. In general, however, the doses of propyphenazone usual in the practice for the treatment of acute feverish infections no disturbing effects of induction or inhibition on the metabolic liver functions represented by the amino-N-demethylation are to be expected. The enzyme-inducing effect of Wofapyrin "new" is to be ascribed to the phenyl-butazone component.