Aripiprazole

Mechanism :

It is an atypical anti-psychotic. However, unlike the other atypical antipsychotics, it is a partial agonist at dopamine D2 and serotonin type 1 (5-HT1A) receptors. It is also an antagonist at serotonin type 2 (5-HT2A) receptor and has alpha-blocking activity. It also acts as a partial agonist at the 5-HT2C receptor with high affinity. and this may underlie the minimal weight gain seen in the course of therapy.

Indication :

• Bipolar disorder
• Schizophrenia
• Autism
• Tourette syndrome

Contraindications :

Hypersensitivity to the aripiprazole or its components.

Dosing :

Adverse Effect :

Headache, agitation, insomnia, anxiety, dizziness, light headedness, somnolence, tremors, extrapyramidal signs, blurred vision, neuroleptic malignant syndrome, seizure, tardive dyskinesia, altered mental status, autonomic instability, nausea, vomiting, constipation, dry mouth/xerostomia, dysphagia, orthostatic hypotension, stiffness, myalgia, rash, weight gain, fatigue, restlessness, hyperpyrexia.

Interaction :

Carbamazepine: Can markedly decrease the amount of aripiprazole in the body by increasing the rate at which the body's enzymes (particularly the liver enzyme, CYP3A4) degrade it. The dose of aripiprazole should therefore be doubled when used with carbamazepine. Other drugs that can promote the activity of CYP3A4 and decrease the body's levels of aripiprazole are phenytoin, rifampin and phenobarbital.
Ketoconazole: Can increase the amount of aripiprazole in the body by blocking CYP3A4. Aripiprazole’s dose should be reduced by one-half during ketoconazole therapy. Many other drugs also are known to block CYP3A4 and potentially could increase the levels of aripiprazole. These drugs include: itraconazole, fluconazole, voriconazole, cimetidine, verapamil, diltiazem, erythromycin, clarithromycin, nefazodone, ritonavir, saquinavir, nelfinavir, indinavir and grapefruit juice.
Quinidine: Inhibits another liver enzyme known as CYP2D6 that also breaks down aripiprazole and can increase the amount of aripiprazole in the body. It is recommended to reduce the dose of aripiprazole by one-half during quinidine therapy. Other medicines that block CYP2D6 include fluoxetine and paroxetine.
Alpha-1 receptor blockers [Doxazosin, Prazosin, Terazosin], used for control of blood pressure and prostatic enlargement: May increase the chance of hypotension.

Renal Dose :

Hepatic Dose :