Antipanic drug effects during lactate infusion in lactate-refractory panic patients

In previous articles we have reported on the total Acute Panic Inventory (API) score during lactate-induced panic. Even patients with panic disorder who do not panic during lactate infusion have higher API scores during the infusion than normal controls. In this post hoc analysis, we wished to determine whether specific API items were more sensitive to the beneficial effects of antipanic medication, either at baseline or during the infusion, in these lactate- insensitive panic patients. Four of the 17 items showed specific drug blockade of baseline severity. Five additional items showed specific drug blockade of lactate exacerbation of symptom severity. Medication apparently had no effect on severity of the remaining eight items. We suggest that the nine symptoms that responded to drug therapy are associated with hyperventilation. The study indicates that antipanic drugs may have a specific effect in blunting hyperventilation.