[Metabolic interactions of propyphenazone]

Pretreatment of female Wistar rats with propyphenazone produces a slight shortening of the hexobarbital sleeping time, and high doses of this drug cause a small increase in the relative liver weight, but there occurs no significant change in the N-demethylation of aminophenazone, the O-demethylation of codeine phosphate, the hydroxylation of aniline, the glucuronidation of p-nitrophenol, the cytochrome P-450 concentration and the NADPH-cytochrome c reductase activity in the 9.000 supernatant of liver homogenates. The differences between these properties of propyphenazone and those of aminophenazone and phenazone are discussed with reference to partition coefficients and biotransformation. The findings obtained do not justify the expectation of metabolic drug-drug interactions in case of repeated application of propyphenazone in the framework of a combined therapy.