Past Issues
Aripiprazole-induced Acute Dystonia in a Methylphenidate-medicated
Boy Patient with Aattention-defi cit/hyperactivity Disorder
Yu-Hsin Huang, Chau-Shoun Lee
Background: Aripiprazole has been increasingly used in children and adolescents
with psychiatric disorders. Few investigations on aripiprazole-induced extrapyramidal
symptom have been performed in those young patients. We report a boy
with aripirazole-induced acute dystonia. Case Report: A 10-year-old boy developed
acute dystonia one week after the treatment with 2.5 mg aripiprazole per day
for his tic-like symptom. He had taken methylphenidate fi ve months before this
adverse event for his attention-defi cit/hyperactivity disorder. The adverse drug reaction
probability scale was used and showed a probable relationship. Conclusion:
We postulated two mechanisms. First, physiologic variations in pharmacokinetics
among children, like the lower activities of cytochrome P450 (CYP)
isoenzymes, CYP2D6 and CYP3A4, might enhance the risk. Second, the sensitivity
of D2 receptors is vulnerable to change at the administration of dopaminergic
agents. Methylphenidate would increase the synaptic level of dopamine, making
aripiprazole like a D2 antagonist to induce acute dystonia thereafter.
with psychiatric disorders. Few investigations on aripiprazole-induced extrapyramidal
symptom have been performed in those young patients. We report a boy
with aripirazole-induced acute dystonia. Case Report: A 10-year-old boy developed
acute dystonia one week after the treatment with 2.5 mg aripiprazole per day
for his tic-like symptom. He had taken methylphenidate fi ve months before this
adverse event for his attention-defi cit/hyperactivity disorder. The adverse drug reaction
probability scale was used and showed a probable relationship. Conclusion:
We postulated two mechanisms. First, physiologic variations in pharmacokinetics
among children, like the lower activities of cytochrome P450 (CYP)
isoenzymes, CYP2D6 and CYP3A4, might enhance the risk. Second, the sensitivity
of D2 receptors is vulnerable to change at the administration of dopaminergic
agents. Methylphenidate would increase the synaptic level of dopamine, making
aripiprazole like a D2 antagonist to induce acute dystonia thereafter.
| Key Word | adverse effects, aripiprazole, dystonia, methylphenidate |
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