Drug Interactions between Cheratussin AC and fezolinetant

CONTRAINDICATED: Coadministration with inhibitors of CYP450 1A2 such as caffeine may significantly increase the plasma concentrations of fezolinetant, which is primarily metabolized by the isoenzyme. The interaction has not been studied with caffeine but has been reported for other CYP450 1A2 inhibitors. Consumption of caffeine-containing food or beverages (e.g., chocolate, coffee, cola drinks, energy drinks, tea) could result in an interaction with fezolinetant. In clinical drug interaction studies, fezolinetant was coadministered with fluvoxamine, mexiletine, and cimetidine (potent, moderate, and weak CYP450 1A2 inhibitors, respectively). Fezolinetant peak plasma concentration (Cmax) increased by 80%, 40%, and 30%, respectively, while its systemic exposure (AUC) increased by 840%, 360%, and 100%, respectively.

MANAGEMENT: Concomitant use of fezolinetant with CYP450 1A2 inhibitors such as caffeine, including caffeine-containing food or beverages, is considered contraindicated.

GENERALLY AVOID: Ethanol may potentiate the central nervous system (CNS) depressant effects of opioid analgesics. Concomitant use may result in additive CNS depression and impairment of judgment, thinking, and psychomotor skills. In more severe cases, hypotension, respiratory depression, profound sedation, coma, or even death may occur.

MANAGEMENT: Concomitant use of opioid analgesics with ethanol should be avoided.