Mirtazapine has been explored as a treatment option for fibromyalgia due to its blockade of 5-HT2 and 5-HT3 receptors.66 In a 6-week open-label trial involving 29 patients with fibromyalgia who received mirtazapine at doses of 15–30 mg/day, 54% of the 26 patients who completed the study reported a clinically significant reduction in pain intensity and their mean weekly acetaminophen dosage.46,66. The gene discussed is HTR2A; the disease is fibromyalgia.