Coadministration with opioids such as methadone, hydrocodone, oxycodone and fentanyl may result in a drop in opioid plasma concentrations, because<unk>  is an inducer of the CYP3A4 enzymes. If not monitored closely, reduced efficacy or withdrawal symptoms can occur.<unk>  may have an adverse effect on hormonal contraceptives for up to a month after discontinuation. In a 2006 study, a single dose of<unk>  200 mg caused a decrease in blood prolactin levels, although it did not affect human growth hormone or thyroid-stimulating hormone. Since<unk>  can induce the activity of the CYP3A4 enzyme involved in cortisol clearance,<unk>  may reduce the bioavailability of hydrocortisone. Therefore, it may be necessary to adjust the steroid substitution dose in subjects receiving CYP3A4-metabolism-inducing drugs such as<unk> .<unk>  is classified as a weak to moderate inducer of CYP3A4.
Modafinil
Armodafinil
Methylphenidate
Adrafinil
Dexmethylphenidate
Ethylphenidate
Dimethazan
Fluparoxan