Drug Interactions between aripiprazole and Pyrelle HB

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of aripiprazole and its active metabolite, dehydro-aripiprazole. Clinical and in vitro data indicate that aripiprazole is extensively metabolized in the liver primarily via three enzymatic pathways (dehydrogenation, hydroxylation, and N-dealkylation) mediated by CYP450 2D6 and 3A4. When aripiprazole 30 mg once daily was coadministered with the potent CYP450 3A4 inducer carbamazepine at 200 mg twice daily in schizophrenic patients, mean aripiprazole peak plasma concentration (Cmax) and systemic exposure (AUC) decreased by 68% and 73%, respectively, compared to administration of aripiprazole alone. Likewise, mean Cmax and AUC of dehydro-aripiprazole were decreased by 69% and 71%, respectively, in the presence of carbamazepine. The interaction has not been studied with other, less potent inducers.

MANAGEMENT: Pharmacologic response to aripiprazole should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the aripiprazole dosage adjusted as necessary. The prescribing information for individual aripiprazole products should be consulted for specific recommendations regarding concomitant use with CYP450 3A4 inducers.

Switch to consumer interaction data

MONITOR: Agents with anticholinergic properties (e.g., sedating antihistamines; antispasmodics; neuroleptics; phenothiazines; skeletal muscle relaxants; tricyclic antidepressants; disopyramide) may have additive effects when used in combination. Excessive parasympatholytic effects may result in paralytic ileus, hyperthermia, heat stroke, and the anticholinergic intoxication syndrome. Peripheral symptoms of intoxication commonly include mydriasis, blurred vision, flushed face, fever, dry skin and mucous membranes, tachycardia, urinary retention, and constipation. Central symptoms may include memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures. Central nervous system-depressant effects may also be additively or synergistically increased when these agents are combined, especially in elderly or debilitated patients. Use of neuroleptics in combination with other neuroleptics or anticholinergic agents may increase the risk of tardive dyskinesia. In addition, some neuroleptics and tricyclic antidepressants may cause prolongation of the QT interval and theoretically, concurrent use of two or more drugs that can cause QT interval prolongation may result in additive effects and increased risk of ventricular arrhythmias including torsade de pointes and sudden death.

MANAGEMENT: Caution is advised when agents with anticholinergic properties are combined, particularly in the elderly and those with underlying organic brain disease, who tend to be more sensitive to the central anticholinergic effects of these drugs and in whom toxicity symptoms may be easily overlooked. Patients should be advised to notify their physician promptly if they experience potential symptoms of anticholinergic intoxication such as abdominal pain, fever, heat intolerance, blurred vision, confusion, and/or hallucinations. Ambulatory patients should be counseled to avoid activities requiring mental alertness until they know how these agents affect them. A reduction in anticholinergic dosages may be necessary if excessive adverse effects develop.

Switch to consumer interaction data