Anxiogenic effects of Sumatriptan in panic disorder: A double-blind, placebo-controlled study

Background: Several lines of evidence point to serotonergic abnormalities in patients with panic disorder (PD). Our goal was to further examine central serotonergic function in panic patients using autonomic and subjective responses to the postsynaptic serotonin 5-HT_1D receptor agonist Sumatriptan. Method: Using a double-blind, randomized, placebo-controlled design, we assessed autonomic and subjective responses to oral Sumatriptan (100 mg) and placebo in 15 patients with PD, free of medication. Subjective responses were measured using the Hamilton Anxiety Rating Scale (HAM-A), National Institute of Mental Health Anxiety Scale (NIMHA), a modified version of the Panic Symptom Inventory (PI), Hamilton Depression Rating Scale (HAM-D), and Montgomery-Asberg Depression Rating Scale (MADRS). Results: PD patients exhibited significantly enhanced autonomic and subjective responses following challenge with Sumatriptan. We observed an increased pulse rate and augmentation of various parameters measured on different anxiety scales. A constant inclination of aggravation of the measured parameters was detected during the hour post challenge. Conclusion: Oral administration of Sumatriptan, a 5-HT_1D agonist, has been associated with an anxiogenic effect in PD patients.