Dose Equivalence Between Abilify Maintena 400 mg and Abilify Aristada 882 mg
Abilify Aristada 882 mg delivers approximately double the aripiprazole exposure compared to Abilify Maintena 400 mg monthly, which is why Aristada 882 mg can be dosed every 6 weeks instead of monthly.
Pharmacokinetic Basis for Dosing Differences
Formulation and Release Characteristics
Abilify Maintena 400 mg is aripiprazole monohydrate administered once monthly, achieving steady-state plasma concentrations of 93-112 ng/mL after 4 weeks, which falls within the established therapeutic window of 94.0-534.0 ng/mL 1
Abilify Aristada 882 mg is aripiprazole lauroxil (a prodrug), available in 441 mg, 662 mg, and 882 mg strengths, with the 882 mg dose specifically designed for extended dosing intervals 2
Actual Dose Relationship
The 882 mg Aristada formulation provides sufficient aripiprazole exposure to maintain therapeutic levels for 6-week dosing intervals, whereas Maintena 400 mg requires monthly administration 2
This means Aristada 882 mg every 6 weeks delivers roughly equivalent total drug exposure as Maintena 400 mg every 4 weeks, accounting for the different release kinetics and prodrug conversion 2
Clinical Implications
Therapeutic Equivalence Considerations
Both formulations maintain aripiprazole plasma concentrations within the therapeutic range established for oral aripiprazole (10-30 mg/day), which corresponds to plasma levels of 94.0-534.0 ng/mL 1
The 400 mg starting dose of Maintena was the appropriate initiation dose for 90.1% (1296/1439) of patients across clinical studies, with low discontinuation rates due to lack of efficacy (2.3%-10.0%) 1
Aristada 441 mg and 882 mg monthly dosing demonstrated efficacy in acute, double-blind, placebo-controlled trials comparable to Maintena 2
Practical Dosing Context
Aripiprazole exhibits mean elimination half-lives of approximately 75 hours for aripiprazole and 94 hours for its active metabolite dehydroaripiprazole, requiring 14 days to reach steady-state 3
The optimal oral aripiprazole dose is 10 mg/day, with the highest response rates seen at this dose, and doses above 20 mg/day providing no additional benefit 4
For long-acting formulations, both Maintena 400 mg monthly and Aristada 882 mg every 6 weeks are designed to maintain plasma levels equivalent to effective oral dosing of 10-30 mg/day 1, 2