Drug Interaction Report

GENERALLY AVOID: Coadministration with potent inducers of CYP450 3A4 may decrease the plasma concentrations of fruquintinib, which is primarily metabolized by the isoenzyme. Concomitant use with rifampin, a potent CYP450 3A4 inducer, decreased fruquintinib peak plasma concentration (Cmax) and systemic exposure (AUC) by 12% and 65%, respectively. Reduced efficacy of fruquintinib may occur.

MANAGEMENT: Coadministration of fruquintinib with potent CYP450 3A4 inducers should be avoided.

ADJUST DOSING INTERVAL: Fat-rich food enhances the absorption of mitotane. One study evaluated blood levels of mitotane (o,p'-DDD) after subjects ingested a single dose of 2 g administered using various delivery vehicles (e.g., tablets, granules, milk, chocolate or oil emulsion). Mitotane plasma levels were significantly higher for milk, chocolate, and oil emulsion when compared to those who received tablets or granules alone. In the same study, mitotane levels were evaluated in subjects following long-term treatment (total dose of 200 g over 30 to 60 days) in tablet, oil emulsion, or milk formulations. Significantly higher mean plasma levels were recorded in subjects who received mitotane as an oil emulsion or mixed in milk, when compared to tablets alone. Additionally, the recovery of o,p'-DDD from the feces was about 5 times higher in subjects who received tablets alone, suggesting absorption was reduced when compared to subjects who received mitotane mixed with a fat-rich vehicle (e.g., oil emulsion or milk).

GENERALLY AVOID: Concomitant use of mitotane with central nervous system (CNS) depressants, including alcohol, may potentiate adverse effects such as somnolence and sedation.

MANAGEMENT: According to product labeling, mitotane tablets should be taken during meals containing fat-rich food (e.g., milk, chocolate, or oil) and with a full glass of water. Patients should be advised to avoid or limit consumption of alcohol and to avoid activities requiring mental alertness such as driving or operating hazardous machinery until they know how the medication affects them.