Serotonin syndrome after the use of tramadol and ziprasidone in a patient with a deep brain stimulator for Parkinson disease.

Serotonin syndrome (SS) is a life-threatening adverse reaction that can result from the therapeutic use of serotonergic drugs or accidental drug interactions. Tramadol is a drug that is widely prescribed because of its low abuse potential, but physicians need to be aware of its significant potential to cause SS because it inhibits serotonin reuptake. Ziprasidone is an atypical antipsychotic that can also cause dangerous interactions to cause SS because it is not only a potent 5-HT1A agonist but also has been reported to inhibit serotonin reuptake with an affinity similar to tricyclic antidepressants, in addition to inhibiting reuptake of norepinephrine. We are describing the clinical characteristics of a gentleman with bipolar disorder and Parkinson disease who presented with SS, despite having a deep brain stimulator in the subthalamic nucleus, which decreases central serotonin levels, and a discussion of the factors that contributed to his presentation.