MH PHARM | Aripiprazole

Aripiprazole Overview & Mechanism of Action Aripiprazole is an atypical antipsychotic acting as a partial agonist at dopaminergic D2 and serotonergic 5-HT1A receptors, and an antagonist at 5-HT2A receptors. This unique mechanism stabilizes dopamine, limiting extrapyramidal side effects compared to older agents. It is FDA-approved for schizophrenia, bipolar I disorder, major depressive disorder (MDD) adjunct therapy, Tourette's syndrome, and autism-associated irritability.Critical Boxed WarningsSuicidality: There is an increased risk of suicidal thoughts and behaviors in children, adolescents, and young adults (up to 24 years of age) when aripiprazole is used as an antidepressant.Dementia-Related Psychosis: Antipsychotics are not approved for treating dementia-related psychosis in the elderly due to significantly elevated mortality (often from heart failure or pneumonia) and cerebrovascular events like stroke.Formulations & Administration ProtocolsOral Options: Available as immediate-release tablets, disintegrating tablets, oral solutions, and Mycite. Mycite contains an ingestible sensor tracked via a smartphone app, though it is not recommended for "real-time" emergency tracking. All oral forms may be administered without regard to meals.Short-Acting IM Injection: Utilized exclusively for acute agitation in schizophrenia or bipolar mania. Inject deeply into the muscle; intravenous and subcutaneous routes are strictly contraindicated.Extended-Release (LAI) IM Injections: Formulations like Abilify Maintena (monthly), Abilify Asimtufii (every 2 months), and Aristada provide maintenance therapy via deep gluteal or deltoid injection. LAIs are not approved for patients under 18 years of age. Crucial Rule: Tolerability with oral aripiprazole must be established (which takes up to 2 weeks) prior to initiating long-acting injections in aripiprazole-naive patients. Initiation requires 14 to 21 days of oral overlap or the use of Aristada Initio.Key Dosing PrinciplesSchizophrenia & Bipolar I: Initiate at 10 to 15 mg/day PO for adults. The target maximum effective dose is 30 mg/day.MDD Adjunct: Start at 2 to 5 mg/day PO, adjusting up to 15 mg/day based on response.Pediatrics: Doses vary by weight and indication, with maximum PO doses of 30 mg/day for bipolar disorder, 15 mg/day for autism, and 20 mg/day for Tourette's.Adjustments: Aripiprazole undergoes extensive hepatic metabolism via CYP3A4 and CYP2D6. Dosages must be reduced by 50% to 75% in CYP2D6 poor metabolizers or when co-administered with strong CYP3A4 or CYP2D6 inhibitors. No hepatic or renal dose adjustments are required.Pharmacokinetics & Safety Profile Oral aripiprazole has an 87% bioavailability, achieving steady-state within 14 days with an elimination half-life of 75 hours. LAI half-lives range widely from 30 to 57 days. Common mild-to-moderate adverse reactions include headache (0-27%), weight gain (2.2-26.3%), drowsiness (3-23%), agitation (19%), and nausea (8-15%). Severe risks include tardive dyskinesia, neuroleptic malignant syndrome, seizures, and metabolic changes.