[Effect of thiamine and riboflavin derivatives on the activity of xenobiotic-metabolizing enzyme and on the pharmacologic effect of analgesics].

Riboflavin deficiency decreases the activity of rat hepatic microsomal enzymes, addition of riboflavin and flavin mononucleotide stimulates their activity. At the same time thiamine deficiency induces xenobiotic metabolic enzymes and excessive addition of thiamine, thiamine diphosphate in particular, suppresses their activity. Flavin mononucleotide and thiamine diphosphate considerably modify the pharmacological effect of the agents which are actively metabolized by the hepatic microsomal system. Thiamine diphosphate enhances the pharmacological activities of orthophen, indomethacin, and tramal while flavin mononucleotide slightly diminishes them.