Aripiprazole is a second-generation antipsychotic. Similar to other second-generation antipsychotics, its exact mechanism of action is unknown. The Abilify Maintena summary of product characteristics states that aripiprazole's efficacy in schizophrenia may be mediated through a combination of partial agonist activity at dopamine D2 and serotonin 5-HT1A receptors and antagonist activity at serotonin 5-HT2A receptors.
In November 2013, aripiprazole prolonged-release suspension for injection (Abilify Maintena; a new, once-monthly formulation of aripiprazole) was granted a European marketing authorisation. It is licensed for maintenance treatment of schizophrenia in adults whose condition has been stabilised with oral aripiprazole. It was launched in the UK in January 2014.
The once-monthly formulation of aripiprazole is provided as powder and solvent for prolonged-release suspension for injection. Each single-use vial contains aripiprazole 400 mg. It is intended for intramuscular injection into the gluteal muscle and should only be administered by a healthcare professional.
The recommended starting and maintenance dose is 400 mg once monthly (no sooner than 26 days after the previous injection) as a single injection. Titration of the dose is not needed. After the first injection, treatment with oral aripiprazole (10–20 mg) should be continued for 14 consecutive days to maintain therapeutic aripiprazole concentrations during initiation of therapy. If adverse events occur, reduction of the monthly dose to 300 mg should be considered (a 300 mg dose would be given from a 400 mg vial, if needed). In addition, dosage adjustments may be needed in people who are known to be CYP2D6 poor metabolisers, and people who are taking certain concomitant medications (see the Abilify Maintena summary of product characteristics for more information).
The summary of product characteristics states that for people who have never taken aripiprazole, tolerability to oral aripiprazole should be established before starting treatment with aripiprazole prolonged-release suspension for injection.
The cost of 1 vial of Abilify Maintena 400 mg powder and solvent for prolonged-release suspension for injection for monthly use is £220.41 (MIMS March 2014).