Abstract
Effect of p-hydroxyacetanilide, the metabolite of acetophenetidine and acetanilide, when used in combination with aminopyrine, antipyrine, and isopropylantipyrine, the antifebrile-analgesic of pyrazolone system, on the metabolism of these agents was examined by measuring the metabolic rate with rat and rabbit liver specimens and in 9000xg supernatant fraction from rat liver, and blood level in rabbit. 1) p-Hydroxyacetanilide hardly affects the metabolism of aminopyrine and 4-isopropylantipyrine in rat and rabbit liver enzyme system, or blood level in rabbit. 2) Metabolism of antipyrine is inhibited by p-hydroxyacetanilide and blood level of antipyrine is maintained longer. 3) Metabolism of p-hydroxyacetanilide is inhibited by antipyrine and its blood level is maintained longer by antipyrine. 4) Penetration of antipyrine and p-hydroxyacetanilide through the excised intestine is mutually inhibited by the other agent. These results show that p-hydroxyacetanilide affects the metabolism of antipyrine but not that of other agents.
