Chronic Serotonergic Overstimulation Mimicking PanicAttacks in a Patient with Parkinson’s Disease Receiving AdditionalAntidepressant Treatment with Moclobemide

The pharmacological treatment options of Parkinson’s disease (PD) have considerably evolved during the last decades.However, therapeutic regimes are complicated due to individual differences in disease progression as well as the occurrence of complexnonmotor impairments such as mood and anxiety disorders. Antidepressants in particular are commonly prescribed for the treatmentof depressive symptoms and anxiety in PD.Case Presentation. In this case report, we describe a case of a 62-year-old female patientwith PD and history of depressive symptoms for which she had been treated with moclobemide concurrent with anti-Parkinsonmedications pramipexole, rasagiline, and L-DOPA+benserazide retard. An increase in the dosage of moclobemide 12 months priorto admission progressively led to serotonergic overstimulation and psychovegetative exacerbations mimicking the clinical picture ofan anxiety spectrum disorder. After moclobemide and rasagiline were discontinued based on the hypothesis of serotonergicoverstimulation, the patient’s psychovegetative symptoms subsided.Conclusions. The specific pharmacological regime in this caseprobably caused drug-drug interactions resulting in a plethora of psychovegetative symptoms. Likely due to the delayed onset ofadverse effects, physicians had difficulties in determining the pharmacologically induced serotonin toxicity. This case reportemphasizes the complexity of pharmacological treatments and the importance of drug-drug interaction awareness in the treatmentof PD patients with complicating nonmotor dysfunctions such as depression.