Attention Deficit Hyperactivity Disorder(ADHD) and Tourrete Syndrome(TS) commonly
co-occur, imposing a special challenge in the management. Case report: This is a case of a nine year old boy with ADHD and TS, who had been on methylphenidate, risperidone, fluvoxamine and atomoxetine, alone and in combination. Tics worsened with methylphenidate but improved after its withdrawal, and the addition of risperidone and fluvoxamine. Later, atomoxetine was added which worsened the tics, even when it was removed. Significant improvement in the tics were only obvious when fluvoxamine was taken off. Discussion: The possible roles of dopamine and serotonin neurotransmission, and metabolism of cytochrome P450 D26 in the pathophysiology were discussed. Conclusion: The use of multiple medications need cautious consideration and monitoring in a child patient to avoid unwanted complications and risks.