The therapeutic efficacy of Cavain should be proved in the treatment of patients suffering from abnormal anxiety, psychosomatic complaints and psychoreactive disorder. Thus two randomized groups of patients (26 each) were treated in double-blind technique with either 2 x 200 mg daily Cavain or placebo for a period of 28 days.

How the excitability of neurons is affected was investigated by determining the interaction of (+/-)-kavain with epitopes (site 1, site 2) of voltage-dependent Na+ channels and the action of (+/-)-kavain on 4-aminopyridine-stimulated synaptosomes as model of repetitive firing neurons. [3H]Saxitoxin and [3H]batrachotoxin were used for radioligand-binding assays performed with synaptosomal membranes. It was shown that (+/-)-Kavain failed to compete with [3H]saxitoxin up to 400 mumol/l but dose-dependently suppressed binding of [3H]batrachotoxin with an IC50 value of 88 mumol/l (Ki = 72 mumol/l) although displacement of [3H]batrachotoxin was restricted to 33% of control at 400 mumol/l (+/-)-kavain.