Drug Interactions between dexamethasone and ramelteon

MONITOR: Coadministration with inducers of CYP450 isoenzymes may decrease the plasma concentrations and pharmacologic effects of ramelteon, which is metabolized by CYP450 1A2 and, to a lesser extent, by CYP450 3A4 and the 2C subfamily of isoenzymes. When a single 32 mg oral dose of ramelteon was administered to healthy volunteers following pretreatment with the potent CYP450 inducer rifampin (600 mg orally once daily for 11 days), total systemic exposure (AUC) to ramelteon and its pharmacologically active metabolite was decreased by an average of approximately 80% (range 40% to 90%). Use with other inducers has not been adequately studied.

MANAGEMENT: The efficacy of ramelteon may be reduced when prescribed with potent inducers of CYP450 isoenzymes such as carbamazepine, enzalutamide, phenobarbital, phenytoin, rifampin, and St. John's wort. Other known inducers include aminoglutethimide, bexarotene, bosentan, dabrafenib, dexamethasone, efavirenz, etravirine, mitotane, modafinil, nafcillin, nevirapine, rifabutin, rifapentine, barbiturates and various other anticonvulsants, although the extent to which they interact with ramelteon is unknown.