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March 26, 2016
Table of Contents

1 Introduction
Aripiprazole

Wikipedia

 

Aripiprazole ( ; brand names: Abilify , Abilify Discmelt , Aripiprex ) is an atypical antipsychotic and antidepressant used in the treatment of schizophrenia, bipolar disorder, and clinical depression. It was approved by the US Food and Drug Administration (FDA) for schizophrenia on November 15, 2002, for acute manic and mixed episodes associated with bipolar disorder on October 1, 2004, as an adjunct for major depressive disorder on November 20, 2007 and to treat irritability in children with autism on 20 November 2009. Aripiprazole was developed by Otsuka in Japan, and in the United States, Otsuka America markets it jointly with Bristol-Myers Squibb.




Schizophrenia

Aripiprazole has been approved by the FDA for the treatment of schizophrenia.

Bipolar disorder

Aripiprazole has been approved by the FDA for the treatment of acute manic and mixed episodes, in both pediatric patients aged 10???17 and in adults.

Aripiprazole's use as a monotherapy in bipolar depression is more controversial. While a few pilot studies have found some effectiveness

Major depression (Unipolar depression)

In 2007, aripiprazole was approved by the FDA for the treatment of unipolar depression when used adjunctively with an antidepressant medication. It has not been FDA-approved for use as monotherapy in unipolar depression.

Autism

In 2009, the United States FDA approved Abilify to treat irritability in persons with autism. It was approved on the basis of two studies that showed it reduced aggression towards others, self-injury, quickly changing moods, and irritability.

Cocaine Dependency

Perhaps owing to its mechanism of action relating to dopamine receptors, there is some evidence to suggest that aripiprazole blocks cocaine-seeking behaviour in animal models without significantly affecting other rewarding behaviours (such as food self-administration).




  • D2 Partial Agonist (Ki = 0.34 nM)

  • D3 Antagonist (Ki = 0.8 nM)

  • D4 Antagonist (Ki = 44 nM)

  • 5-HT1A Partial Agonist (Ki = 0.34 nM)

  • 5-HT2A Antagonist (Ki = 0.8 nM)

  • 5-HT2C Partial Agonist (Ki = 15 nM)

  • 5-HT7 Antagonist (Ki = 39 nM)

  • SRI (Ki = 98 nM)

  • Antihistamine (Ki = 61 nM)

  • ??-adrenergic antagonist (Ki = 57 nM)

  • mACh receptor antagonist (IC50 >1000 nM)

Aripiprazole's mechanism of action is different from those of the other FDA-approved atypical antipsychotics (e.g., clozapine, olanzapine, quetiapine, ziprasidone, and risperidone). Rather than antagonizing the D2 receptor , aripiprazole acts as a D2 partial agonist (Ki = 0.34 nM). Aripiprazole has moderate affinity for histamine (Ki = 61 nM), ??-adrenergic (Ki = 57 nM), and D4 receptors as well as the serotonin transporter, while it has no appreciable affinity for cholinergic muscarinic receptors.

D2 and D3 receptor occupancy levels are high, with average levels ranging between ~71% at 2 mg/day to ~96% at 40 mg/day.

Most atypical antipsychotics bind preferentially to extrastriatal receptors, but aripiprazole appears to be less preferential in this regard, as binding rates are high throughout the brain.

Recently, it has been demonstrated that in 5-HT7 receptor knockout mice , aripiprazole does not reduce immobility time in the forced swim test (FST), and actually increases it.

Aripiprazole produces 2,3-dichlorophenylpiperazine (DCPP) as a metabolite similarly to how trazodone and nefazodone reduce to 3-chlorophenylpiperazine ( m CPP) and niaprazine converts to 4-fluorophenylpiperazine (pFPP). It is unknown whether DCPP contributes to aripiprazole's pharmacology in any way, but the possibility cannot be excluded.




Aripiprazole displays linear kinetics and has an elimination half-life of approximately 75 hours. Steady-state plasma concentrations are achieved in about 14 days. Cmax (maximum plasma concentration) is achieved 3???5 hours after oral dosing. Bioavailability of the oral tablets is about 90% and the drug undergoes extensive hepatic metabolization (dehydrogenation, hydroxylation, and N-dealkylation), principally by the enzymes CYP2D6 and CYP3A4. Its only known active metabolite is dehydro-aripiprazole, which typically accumulates to approximately 40% of the aripiprazole concentration. The parenteral drug is excreted only in traces, and its metabolites, active or not, are excreted via feces and urine. When dosed daily, brain concentrations of aripiprazole will increase for a period of 10???14 days, before reaching stable constant levels. This phenomenon is due to the long half life of aripiprazole, and is responsible for many of the adverse side effects that appear after multiple days of dosing (whereas the first dose normally does not cause these side effects).




Otsuka's US patent on aripiprazole expires on October 20, 2014;

however, due to a pediatric extension, a generic will not become available until at least April 20, 2015. Barr Laboratories (now Teva Pharmaceuticals) initiated a patent challenge under the Hatch-Waxman Act in March 2007. , this challenge is still in court.




Akathisia, headache, unusual tiredness or weakness, nausea, vomiting, an uncomfortable feeling in the stomach, constipation, light-headedness, insomnia, sleepiness, shaking, and blurred vision.

Uncontrollable twitching or jerking movements, tremors, seizure, and weight gain. Some people may feel dizzy, especially when getting up from a lying or sitting position, or may experience a fast heart rate.

Neuroleptic malignant syndrome (Combination of fever, muscle stiffness, faster breathing , sweating, reduced consciousness, and sudden change in blood pressure and heart rate.)

Aripiprazole also causes sexual dysfunction.

Tardive dyskinesia (As with all antipsychotic medication, patients using aripiprazole may develop the permanent neurological disorder tardive dyskinesia.)

Stroke (While taking aripiprazole some elderly patients with dementia have suffered from stroke or 'mini' stroke .)

Other elderly patients may experience high blood sugar or the onset or worsening of diabetes.

Allergic reaction (such as swelling in the mouth or throat, itching, rash), increased production of saliva, speech disorder, nervousness , agitation , fainting, reports of abnormal liver test values, inflammation of the pancreas , muscle pain, weakness, stiffness, or cramps.




Children or adults who ingested acute overdoses have usually manifested central nervous system depression ranging from mild sedation to coma; serum concentrations of aripiprazole and dehydroaripiprazole in these patients were elevated by up to 3-4 fold over normal therapeutic levels, yet no deaths have yet been recorded.




Aripiprazole is a substrate of CYP2D6 and CYP3A4. Coadministration with medications that inhibit (e.g. paroxetine, fluoxetine) or induce (e.g. carbamazepine) these metabolic enzymes are known to increase and decrease, respectively, plasma levels of aripiprazole. As such, anyone taking Abilify should be aware that their dosage of Abilify may need to be decreased.

Aripiprazole may change the subjective effects of alcohol. One study

found that aripiprazole increased the sedative effect and reduced the sense of euphoria normally associated with alcohol consumption. However, another alcohol study

found that there was no difference in subjective effect between a placebo group and a group taking aripiprazole.




  • Intramuscular injection, solution: 9.75 mg/mL (1.3 mL)

  • Tablet: 2 mg, 5 mg, 10 mg, 15 mg, 20 mg, 30 mg






  • Abilify website

  • Abilify Full Prescribing Information (for Health Care Professionals)

  • U.S. National Library of Medicine: Drug Information Portal - Aripiprazole



This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Aripiprazole".


Last Modified:   2010-11-29


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