<p>ketoconazole, itraconazole, erythromycin and grapefruit juice may inhibit its metabolism (increasing serum levels of mifepristone). Furthermore, rifampicin, dexamethasone, St John&#39;s Wort and certain anticonvulsants (phenytoin, phenobarbital, carbamazepine) may induce mifepristone metabolism (lowering serum levels of Mifepristone).&nbsp;Based on invitro inhibition information, co-administration of mifepristone may lead to an increase in serum levels of drugs that are CYP3A4 substrates.<br />
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Limited evidence suggests that co-administration of NSAIDs on the day of prostaglandin administration does not adversely influence the effects of Mifepristone or the prostaglandin on cervical ripening or uterine contractility and does not reduce the clinical efficacy of medical termination of pregnancy.</p>