<p>Drugs known to induce the hepatic cytochrome-P450-3A4 system (e.g. rifampicin, carbamazepine or phenytoin) may increase the elimination rate and thereby decrease the bioavailability of progesterone. The effect of concomitant vaginal products on the exposure of progesterone from Micronized Progesterone has not been assessed and is therefore not recommended.</p>