Rexulti Drug Interactions

Brexpiprazole is predominantly metabolised by CYP3A4 and CYP2D6.
Potential for other medicinal products to affect brexpiprazole: CYP3A4 inhibitors: Co-administration of ketoconazole (200 mg twice daily for 7 days), a potent inhibitor of CYP3A4, with a 2 mg single oral dose of brexpiprazole increased the AUC of brexpiprazole by 97 % and no change in C_max. Based on results of interaction studies, dose adjustment of brexpiprazole to half the dose is recommended when administered concomitantly with strong CYP3A4 inhibitors (itraconazole, ketoconazole, ritonavir, and clarithromycin).
CYP3A4 inducers: Co-administration of rifampicin (600 mg twice daily for 12 days), a potent CYP3A4 inducer, with a single 4 mg oral dose of brexpiprazole resulted in an approximate 31 % and 73 % decrease in brexpiprazole C_max and AUC, respectively. If brexpiprazole is used concomitantly with strong CYP3A4 inducers (e.g. rifampicin), the total daily dose requirement of brexpiprazole is increased by approximately a factor of three times the recommended daily dose (see Dosage & Administration). Once daily dosing while CYP3A4 inducers are administered results in high peak to trough fluctuation, hence twice daily divided dosing is preferable.
CYP2D6 inhibitors: Co-administration of a 2 mg single oral dose of brexpiprazole with quinidine (324 mg/day for 7 days), a potent inhibitor of CYP2D6, increased the AUC of brexpiprazole by 94 % and no change in C_max. Based on results of interaction studies, dose adjustment of brexpiprazole to half the dose is recommended when administered concomitantly with strong CYP2D6 inhibitors (quinidine, paroxetine, and fluoxetine).
Based on estimations from the population pharmacokinetic analysis, CYP2D6 extensive metabolisers receiving both CYP3A4 and CYP2D6 inhibitors or CYP2D6 poor metabolisers receiving strong CYP3A4 inhibitors are expected to have approximately 4-fold to 5-fold increase in brexpiprazole concentrations and dose adjustment to a quarter of the dose is recommended for these subjects (see Dosage & Administration).
Potential for brexpiprazole to affect other medicinal products: Based on results of in vitro studies, brexpiprazole is unlikely to cause clinically important pharmacokinetic interactions with medicinal products metabolised by cytochrome P450 enzymes. Brexpiprazole does not affect absorption of medicinal products that are substrates of Breast Cancer Resistance Protein transporter (BCRP) and P-glycoprotein (P-gp) transporter.
If brexpiprazole is administered concomitantly with medicinal products known to cause QT prolongation or electrolyte imbalance, caution should be used. 8 If brexpiprazole is administered concomitantly with medicinal products known to increase creatine phosphokinase (CPK) the possible additive effect with CPK increase induced by brexpiprazole should be considered.
Pharmacodynamic interactions: No information on pharmacodynamic interactions of brexpiprazole is available at present. Caution should be exercised when prescribing with other medicinal products. Given the primary Central Nervous System (CNS) effects of brexpiprazole, caution should be used when brexpiprazole is taken in combination with alcohol or other CNS medicinal products with overlapping adverse reactions such as sedation (see Adverse Reactions).