PHARMACOLOGICAL EFFECT OF IMIPRAMINE, PAROXETINE, AND SERTRALINE ON 35-PERCENT CARBON-DIOXIDE HYPERSENSITIVITY IN PANIC PATIENTS - A DOUBLE-BLIND, RANDOM, PLACEBO-CONTROLLED STUDY

The effects of short treatment (7 days) with the tricyclic antidepress ant imipramine and the two selective serotonin reuptake inhibitors par oxetine and sertraline on the reactivity to inhalation of 35% CO2/65% O-2 were compared in 70 panic patients who had positive responses to 3 5% CO2 inhalations. A double-blind, random, placebo-controlled design was applied. Each patient was given the 35% CO2 challenge on days 0 (b efore starting the treatment), 3, and 7. In the placebo group, there w ere no significant changes in the reactivity to 35% CO2 in the three s essions whereas there were significant similar reductions of reactivit y to 35% CO2 in all three drug-treated groups. These results confirm t he good reproducibility of 35% CO2 reactivity and the negligible effec ts of placebo on reactivity to CO2 and suggest that short treatments w ith imipramine, paroxetine, and sertraline decrease reactivity to 35% CO2, possibly as an expression of their antipanic properties.