Aripiprazole

Aripiprazole is unusual in that it blocks D2 receptors but also has high affinity for the presynaptic D2 receptor as an agonist.

Aripiprazole is a partial agonist at 5-HT1A receptors and a strong antagonist at 5-HT2A receptors (R2; R3).

Of all the atypical neuroleptics, aripiprazole also has the lowest affinity for adrenergic, muscarinic, and histamine receptors (R4).

Numerous case reports have reported tic reduction at doses of 2.5 to 30 mg daily. A retrospective assessment of 37 children showed both reduction of tic scores and reduction in tantrums (R5).

A 12-week open-label trial of aripiprazole with 15 pediatric subjects demonstrated significant improvement in all Yale Global Tic Severity Scale (YGTSS) subscales at low doses, early in treatment with a persistent improvement for all subjects (R6).

Murphy et al. (R7) enrolled 16 subjects between the ages of 8–17 to assess safety of aripiprazole in an open-label flexible-dose study. Laboratory measures, extrapyramidal symptoms, electrocardiograms, height, and weight were monitored. They found significant improvement in YGTSS motor, phonic, and total subscales, as well as improvement in obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), and depressive symptoms, but the benefits were tempered by an associated significant weight gain (> 2.5 kg) in half of the subjects. No other significant side effects were reported.

Similarly, Lyon et al. (R8) included 11 subjects with TD between the ages of 9–19 in a 10-week prospective open-label study to test the safety and tolerability of aripiprazole. The mean daily dose of aripiprazole was 4.5 ± 3.0 mg, which was found to reduce YGTSS global severity and tic scores, inattentiveness, hyperactivity, and obsession scores (R8).

They reported that the most common adverse effects included appetite increase, weight gain, headaches, fatigue, and mild extrapyramidal effects. One subject developed akathisia and muscle cramps. (R1)