Drug interactions between Abilify Discmelt and Bellamine S

phenobarbital ↔ aripiprazole

Applies to:Bellamine S (belladonna/ergotamine/phenobarbital) and Abilify Discmelt (aripiprazole)

MONITOR: Coadministration with inducers of CYP450 3A4 may decrease the plasma concentrations of aripiprazole, which is partially metabolized by the isoenzyme. According to the product labeling, administration of aripiprazole (30 mg once a day) with the potent CYP450 3A4 inducer carbamazepine (200 mg twice a day) resulted in an approximately 70% decrease in the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of aripiprazole and its active metabolite, dehydro-aripiprazole.

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Pharmacologic response to aripiprazole should be monitored more closely whenever a CYP450 3A4 inducer is added to or withdrawn from therapy, and the aripiprazole dosage adjusted as necessary.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 manufacturer recommends that aripiprazole dosage be doubled when carbamazepine is added to therapy, and additional dosage increases be based on clinical evaluation. No dosage recommendations are available for concomitant administration with other CYP450 3A4 inducers.

belladonna ↔ aripiprazole

Applies to:Bellamine S (belladonna/ergotamine/phenobarbital) and Abilify Discmelt (aripiprazole)

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.

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.