Clomipramine treatment of hyperventilation syndrome

Six patients suffered from a hyperventilation syndrome for 3.4 +/- 1.2 years. They had a lowered PAco2 at rest and an abnormal CO2 response curve. During the entire period they had received unsuccessful treatment with anxiolytics, and had also undergone behaviour therapy for the last 1 -- 2 years without success. Both treatments were discontinued and the patients were placed on clomipramine, 25 mg t.i.d. for 9 months. Their anxiety and hyperventilation attacks diminished after one month of clomipramine, and their fear of attacks an their phobias subsided after two months. Eighteen months after clomipramine therapy had been initiated, they were feeling well without medication. The possible mode of action of clomipramine on the hyperventilation syndrome via central serotonergic mechanism is discussed.