Exacerbation of tics with combining aripiprazole to pimozide: a case with Tourette’s Syndrome

Tourette Syndrome (TS) is a neuropsychiatric disorder characterized by chronic motor and vocal tics that have a waxing and waning course. There are many pharmacotherapeutic agents considered in the treatment of TS and antipsychotics are the leading ones. Among this group, pimozide is the one whose effectiveness has been proved by controlled randomized trials. Although aripiprazole is highly successful in treating the positive symptoms in schizophrenia and manic symptoms in mania and there is an accumulating data about the improvement of tics with aripiprazole, the evidence of its benefit in TS is restricted with case reports and open trials. We report an adolescent with TS, whose tics exacerbated after addition of aripiprazole to pimozide. Fifteen years old male adolescent was on pimozide regimen for tics when aripiprazole treatment was added for a hypomanic episode. Ten days after the initiation of aripiprazole, the severity of the tics increased and new motor and vocal tics emerged. Although his irritability, psychomotor agitation and other hypomania symptoms improved, aripiprazole was discontinued. The severity of tics declined to its previous level after the cessation of aripiprazole. Aripiprazole has partial agonist effect on dopamine D2 receptors, which is suggested to mediate its dopaminergic effect in hypodopaminergic conditions. This adolescent was on pimozide treatment, a potent dopamine D2 receptor blocker, when aripiprazole was added and it can be suggested that exacerbation of tics was related with partial agonist effect of aripiprazole. We suggest that although aripiprazole have promising effect on treatment of tics, clinicians should be cautious, when combining it with potent antipsychotic agents.