Clonazepam in the treatment of panic disorder: a double-blind, placebo-controlled trial investigating the correlation between clonazepam concentrations in plasma and clinical response.
Thirty-two outpatients with a DSM-III diagnosis of panic disorder or agoraphobia with panic attacks were randomly assigned to 4 weeks of treatment with clonazepam or placebo, after a 1-week placebo washout period. Twenty-nine patients entered the double-blind phase of the study and were eligible for intent-to-treat analysis. Clonazepam-treated patients experienced significantly fewer panic attacks, and these were of lesser intensity and short duration than those in placebo-treated patients (p < 0.001). Clonazepam was also superior to placebo with respect to symptoms of anxiety and depression (p < 0.001). The mean dose of clonazepam at week 4 was 2.2 mg (standard deviation, 0.7 mg). There was significant (p < 0.05) correlation between drug concentration in plasma and decrease in the global measure of the severity of panic disorder (r = 0.68); similar trends were seen for the decreases in frequency (r = 0.60) and severity (r = 0.55) of panic attacks, but not between concentration in plasma and decline in generalized anxiety. The most common adverse event was drowsiness, which occurred in 9 of 13 clonazepam-treated patients.
Beauclair
L
L
Clinical Psychopharmacology Unit, Allan Memorial Institute, Royal Victoria Hospital, Montreal, Quebec, Canada.
Fontaine
R
R
Annable
L
L
Holobow
N
N
Chouinard
G
G
D000328:Adult; D000704:Analysis of Variance; D002998:Clonazepam / Q000097:blood* / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016584:Panic Disorder / Q000188:drug therapy* / Q000523:psychology; D011569:Psychiatric Status Rating Scales
D002998:Clonazepam