Aripiprazoleinteractions

Dosage adjustment due to drug interactions: Factors Dosage Adjustments for Aripiprazole Known CYP2D6 Poor Metabolizers Administer half of usual dose Known CYP2D6 Poor Metabolizers and strong CYP3A4 inhibitors Administer a quarter of usual dose Strong CYP2D6 or CYP3A4 inhibitors Administer half of usual dose Strong CYP2D6 and CYP3A4 inhibitors Administer a quarter of usual dose Strong CYP3A4 inducers Double usual dose over 1 to 2 weeks

7.1 Drugs Having

Clinically Important Interactions with Aripiprazole Table 25: Clinically Important Drug Interactions with Aripiprazole: Concomitant Drug Name or Drug Class Clinical Rationale Clinical Recommendation Strong CYP3A4 Inhibitors (e.g., itraconazole, clarithromycin) or strong CYP2D6 inhibitors (e.g., quinidine, fluoxetine, paroxetine) The concomitant use of aripiprazole with strong CYP3A4 or CYP2D6 inhibitors increased the exposure of aripiprazole compared to the use of aripiprazole alone. With concomitant use of aripiprazole with a strong CYP3A4 inhibitor or CYP2D6 inhibitor, reduce the aripiprazole dosage. Strong CYP3A4 Inducers (e.g., carbamazepine, rifampin) The concomitant use of aripiprazole and carbamazepine decreased the exposure of aripiprazole compared to the use of aripiprazole alone. With concomitant use of aripiprazole with a strong CYP3A4 inducer, consider increasing the aripiprazole dosage. Antihypertensive Drugs Due to its alpha adrenergic antagonism, aripiprazole has the potential to enhance the effect of certain antihypertensive agents. Monitor blood pressure and adjust dose accordingly. Benzodiazepines (e.g., lorazepam) The intensity of sedation was greater with the combination of oral aripiprazole and lorazepam as compared to that observed with aripiprazole alone. The orthostatic hypotension observed was greater with the combination as compared to that observed with lorazepam alone. Monitor sedation and blood pressure. Adjust dose accordingly.

7.2 Drugs Having

No Clinically Important Interactions with Aripiprazole Based on pharmacokinetic studies, no dosage adjustment of aripiprazole is required when administered concomitantly with famotidine, valproate, lithium, lorazepam. In addition, no dosage adjustment is necessary for substrates of CYP2D6 (e.g., dextromethorphan, fluoxetine, paroxetine, or venlafaxine), CYP2C9 (e.g., warfarin), CYP2C19 (e.g., omeprazole, warfarin, escitalopram), or CYP3A4 (e.g., dextromethorphan) when co-administered with aripiprazole. Additionally, no dosage adjustment is necessary for valproate, lithium, lamotrigine, lorazepam, or sertraline when co-administered with aripiprazole..