Double-blind clonazepam vs placebo in panic disorder treatment

OBJECTIVE: To assess the effectiveness of clonazepam, in a fixed dose (2 mg/day), compared with placebo in the treatment of panic disorder patients. METHOD: 24 panic disorder patients with agoraphobia were randomly selected. The diagnosis was obtained using the structured clinical interview for DSM-IV. All twenty-four subjects were randomly assigned to either treatment with clonazepam (2 mg/day) or placebo, during 6 weeks. Efficacy assessments included: change from baseline in the number of panic attacks; CGI scores for panic disorder; Hamilton rating scale for anxiety; and panic associated symptoms scale. RESULTS: At the therapeutic endpoint, only one of 9 placebo patients (11.1%) were free of panic attacks, compared with 8 of 13 (61.5%) clonazepam patients (Fisher exact test; p=0,031). CONCLUSION: the results provide evidence for the efficacy of clonazepam in panic disorder patients.     

Benzodiazepine treatment of panic disorder: a comparison of alprazolam and lorazepam

The antipanic efficacy of alprazolam and lorazepam was evaluated in 48 patients meeting DSM-III criteria for agoraphobia with panic attacks or panic disorder in a double-blind random assignment study. On the basis of rating scale scores, both drugs demonstrated similar efficacy in reducing panic attacks and phobic behavior compared with placebo baseline. The doses required to achieve response were approximately double those required for the treatment of generalized anxiety. These results suggest that most, if not all, benzodiazepines may be effective antipanic drugs at high doses. The implications of these findings for drug treatments of choice for recurrent panic attacks are discussed.     

Double-blind, placebo-controlled assessment of combined clonazepam with paroxetine compared with paroxetine monotherapy for generalized social anxiety disorder

BACKGROUND: Generalized social anxiety disorder (GSAD) is a pervasive form of social anxiety that affects approximately 5% of persons in the community. Among evidence-based pharmacologic treatments for the disorder, selective serotonin reuptake inhibitors (SSRIs) have become widely used and are known to be efficacious. Monotherapy with the benzodiazepine clonazepam is also efficacious for GSAD, but the adjunctive use of clonazepam with an SSRI to potentially improve outcomes has not been studied to date. METHOD: Twenty-eight patients (22 men and 6 women) with DSM-IV-defined GSAD were randomly assigned to receive double-blind clonazepam (or placebo), 1.0 to 2.0 mg/day (divided b.i.d.) along with open-label paroxetine, 20 to 40 mg/day, for 10 weeks. A 2-week taper of double-blind medication was followed by an additional 8 weeks of open-label paroxetine treatment (during which the dose of paroxetine could be increased to a maximum of 50 mg/day). Twenty-three patients (82%) met DSM-IV criteria for avoidant personality disorder. The patients' mean +/- SD age was 31.2 +/- 7.7 years, and their mean duration of illness was 12.1 +/- 5.8 years. Data were gathered from August 2001 to April 2002. RESULTS: Nineteen (68%) of 28 patients completed treatment. At the end of the 10-week double-blind treatment, there was a trend (p <.06) favoring the paroxetine/clonazepam group, who had a 79% response rate (Clinical Global Impressions-Global Improvement scale [CGI-I] score of 1 or 2) compared with a 43% response rate for the paroxetine/placebo group. However, no significant differences on other outcome measures were noted between the 2 groups in an intent-to-treat analysis, in terms of either very early (2-4 weeks) or not as early (5-10 weeks) responses during treatment. Dropout rates due to adverse events were rare (1 patient in each group), indicating that the paroxetine/clonazepam combination was well tolerated. CONCLUSION: Coadministration of clonazepam with an SSRI, in contrast to findings in panic disorder, did not lead to more rapid resolution of symptoms in GSAD. On the other hand, there is some evidence that the clonazepam-added group had superior global outcomes (e.g., as measured on the CGI-I), although power to detect such differences in this study was small. These observations suggest that a role for adjunctive benzodiazepines in patients with GSAD (e.g., for augmenting SSRI partial response or nonresponse) is deserving of further controlled investigation.     

Sodium valproate and clonazepam for treatment-resistant panic disorder.

Sodium valproate (VA) and clonazepam (CLZ) were combined in the treatment of 4 patients with panic disorders (PD) who were resistant to several antipanic drug treatments. A significant improvement was found in the symptomatology of these patients, but relapses occurred when CLZ dosage was reduced. A potentiation of the GABAergic properties of VA and clonazepam is postulated. This combined treatment could be advantageous for some treatment-resistant PD patients but needs to be studied further.     

Treatment of panic disorder and agoraphobia with clonazepam

Clonazepam, a high-potency benzodiazepine marketed for the treatment of minor motor epilepsy, was used to treat 50 patients with panic disorder (N = 22) or agoraphobia with panic attacks (N = 28). Of the 50 patients, 41 had previously been poorly responsive to standard pharmacologic therapies. At a mean dose of only 1.9 (+/- 1.0) mg/day, 39 patients (78%) responded. No serious adverse effects were encountered. This study, although retrospective and uncontrolled, suggests that clonazepam, like alprazolam, may be effective in blocking panic attacks. A possible common mechanism for the two drugs as high-potency benzodiazepines is discussed.     

Early coadministration of clonazepam with sertraline for panic disorder.

BACKGROUND: There is debate about combining benzodiazepines with selective serotonin reuptake inhibitors in the acute treatment of panic disorder. Although this medication combination is widely used in clinical practice, there is no well-tested, optimal method of coadministering these medications for the treatment of panic disorder. The purpose of this study was to test the efficacy of early coadministration of clonazepam with sertraline in the treatment of panic disorder. METHODS: Fifty patients with panic disorder were randomized into a double-blind clinical trial. Patients received open-label sertraline for 12 weeks (target dose, 100 mg/d), and in addition were randomized to groups receiving either 0.5 mg of active clonazepam 3 times daily or placebo clonazepam for the first 4 weeks of the trial. The clonazepam dose was then tapered during 3 weeks and discontinued. RESULTS: Thirty-four (68%) of 50 patients completed the trial. Drop-out rates were similar in the sertraline/placebo vs the sertraline/clonazepam group (38% vs 25%) (P =.5). An intent-to-treat analysis (on last observation carried forward data) revealed a much greater proportion of responders in the sertraline/clonazepam compared with the sertraline/placebo group at the end of week 1 of the trial (41% vs 4%) (P =.003). There was also a significant between-group difference at the end of week 3 with 14 (63%) of 22 of the sertraline/clonazepam group responding to treatment vs 8 (32%) of 25 of the sertraline/placebo group (P =.05). This difference was not observed at other times during the trial. CONCLUSION: These data indicate that rapid stabilization of panic symptoms can be safely achieved with a sertraline/clonazepam combination, supporting the clinical utility of this type of regimen for facilitating early improvement of panic symptoms relative to sertraline alone.     

Double-blind acute clonazepam vs. placebo in carbon dioxide-induced panic attacks

The inhalation of 35% carbon dioxide has consistently been shown to provoke panic attacks in panic disorder patients. We aim to determine if an acute dose of clonazepam (2 mg) attenuates the panic attacks induced by an inhalation of 35% carbon dioxide in panic disorder. Twenty-two panic disorder patients who had been drug-free for 1 week participated in a carbon dioxide challenge test 1 h after a dose of either 2 mg of clonazepam or placebo with a randomized double-blind method. Also in a double-blind design during the tests the patients inhaled either atmospheric compressed air ('placebo control') or the carbon dioxide mixture. All patients participated in both tests which were done with a 20-min interval. Immediately before and after the inhalation, the anxiety levels and the symptoms of panic were always assessed. In the clonazepam group (n=11) two patients (18.2%) had a mild panic attack and in the placebo group (n=11) nine patients (81.8%) had a moderate to severe panic attack in the CO(2) challenge test. No patient had panic attacks during inhalation of atmospheric compressed air although anticipatory anxiety levels tended to be higher than in the CO(2) tests. After the CO(2) test anxiety levels were significantly greater in the CO(2) group (three-way ANOVA with Geisser-Greenhouse adjustments, F(31.92,1.86)=17.15, d.f.=7, P=0.013). Although a small sample was studied, the findings suggest the efficacy of an acute dose of clonazepam in attenuating panic attacks induced by carbon dioxide inhalation.     

Efficacy, safety, and gradual discontinuation of clonazepam in panic disorder: a placebo-controlled, multicenter study using optimized dosages.

BACKGROUND: The purpose of this multicenter, double-blind, placebo-controlled study was to evaluate the efficacy and safety of optimized dosages of clonazepam for the treatment of panic disorder and assess the tolerability of a schedule for gradual discontinuation. METHOD: Adult patients with panic disorder with or without agoraphobia (DSM-III-R criteria) were randomly assigned to receive either placebo or clonazepam in individually adjusted doses over 3 weeks to approximate an optimal dosage, which was then maintained for an additional 3 weeks, amounting to a 6-week therapeutic phase. The daily dose range was 0.25 to 4.0 mg administered in 2 divided doses. In the following 7-week discontinuance phase, the doses were tapered gradually to cessation. RESULTS: At the therapeutic endpoint, clonazepam (N = 222) proved clinically and statistically superior to placebo (N = 216) in change in the number of panic attacks and in Clinical Global Impressions-Severity of Illness (CGI-S) and CGI-Change scores, Patient's Global Impression of Change scores, amount of fear and avoidance associated with phobic symptoms, and duration of anticipatory anxiety. The gradual tapering of clonazepam was not associated with symptoms suggestive of withdrawal syndrome. Although patients taking clonazepam experienced some clinical worsening compared with the status achieved at endpoint, particularly in terms of number of panic attacks, no deterioration was observed using their condition at baseline as point of reference. No overall evidence of rebound was found. All regimens were generally well tolerated. Somnolence was the main adverse event associated with clonazepam therapy. The percentage of patients who reported adverse events was higher in the clonazepam group than in the placebo group, as was the mean number of adverse events per patient. CONCLUSION: In this placebo-controlled trial, clonazepam was an efficacious and safe shortterm treatment of the symptoms of panic disorder. Discontinuance during and after slow tapering was well tolerated.     

Emergence of depressive symptoms in patients receiving alprazolam for panic disorder

The authors relate their clinical experience with 46 panic disorder patients who were receiving 3-10 mg/day of alprazolam. Fifteen (33%) developed symptoms consistent with DSM-III criteria for major depression despite remission of their panic symptoms. Clinicians should be alert to this potentially reversible complication.     

Cognitive style, alprazolam plasma levels, and treatment response in panic disorder

This study investigated an anxiety-prone cognitive style (measured by the Anxious Thoughts and Tendencies Questionnaire, AT&T) as a predictor of the acute response to increasing alprazolam plasma levels in panic disorder. Panic disorder patients (n=26) were treated with escalating doses of alprazolam for 4 weeks, then a fixed dose of 1 mg four times a day for 4 weeks. At 0, 1, 2, 3, 4, 6, and 8 weeks, trough alprazolam plasma levels; clinical, self-report, and performance measures; and vital signs were assessed. Panic attack data were from daily diaries. The repeated response measures were analyzed in relation to alprazolam plasma levels using SAS GENMOD, with patients classified as high or low on the baseline AT&T. Panic attacks, anticipatory anxiety, fear, avoidance, overall agoraphobia, the Hamilton Anxiety Rating Scale, and clinicians' global ratings improved with increasing alprazolam plasma levels. Hopkins Symptom Checklist-90 Anger-Hostility; Profile of Mood States Vigor, Confusion, and Friendliness; and speed and accuracy of performance worsened. Patients with high AT&T scores were worse throughout the study on situational panics, fear, avoidance, overall agoraphobia, the Hamilton Anxiety Rating Scale, the Hamilton Rating Scale for Depression, and Clinical Global Improvement; most Hopkins Symptom Checklist-90 clusters; Profile of Mood States Anxiety, Depression, and Confusion; and Continuous Performance Task omissions. We conclude that in panic disorder: (1) alprazolam has a broad spectrum of clinical activity related to plasma levels in individual patients; (2) sedation, disinhibition, and performance deficits may persist for at least a month after dose escalation ends; (3) marked anxiety-prone cognitions predict more symptoms throughout treatment, but do not modify the response to alprazolam and therefore should not influence the choice of alprazolam as treatment.     

Double-blind comparison of alprazolam, diazepam, and placebo for the treatment of negative schizophrenic symptoms

Fifty-five schizophrenic outpatients with negative symptoms were treated for up to six weeks by the addition of alprazolam (mean dose, 4.2 mg/d), diazepam (mean dose, 40.4 mg/d), or placebo to their ongoing neuroleptic treatment. A repeated-measures analysis of variance with baseline measurements entered as covariates indicated the presence of a significant time X drug interaction effect for the weekly Brief Psychiatric Rating Scale (BPRS) withdrawal/retardation subfactor scores. During the initial weeks of the study, the alprazolam-treated group had lower scores, while the diazepam-treated group had higher scores than the placebo-treated group. However, an end point analysis performed on the final BPRS withdrawal/retardation subfactor scores showed no significant differences among the three groups, nor were beneficial effects observed on any of the BPRS subfactor scores that assess positive symptoms. Plasma alprazolam levels were maintained throughout the study and ranged from 20 to 100 ng/mL. These results suggest that alprazolam had no sustained significant effect on negative schizophrenic symptoms.     

A double-blind, placebo-controlled trial of clonazepam in obsessive-compulsive disorder.

Selective serotonin reuptake inhibitors (SSRIs) are currently the first-line pharmacological agents in treating obsessive-compulsive disorder (OCD). Appropriate treatment for OCD also involves cognitive behavioural therapy (CBT), including exposure and response prevention. As there is a time delay in seeing full therapeutic response, and not all patients tolerate SSRIs, there remains an unmet need for additional treatment approaches in OCD. In addition, most responders report only a partial reduction in symptoms. Clonazepam has demonstrated effectiveness in several preliminary reports in treating OCD. Twenty-seven patients with OCD were entered into a 10 week, double-blind, parallel design trial of clonazepam vs. placebo. Overall, only 3 out of 25 patients who had >/= 1 rating on clonazepam/placebo were judged to be treatment responders, by scoring a 1 (very much improved) or 2 (much improved) on the CGI improvement scale. Responders included 2 of 9 in the placebo group and 1 of 16 in the clonazepam group. No significant difference was found between clonazepam and placebo groups on responder/non responder status (Chi(2 )=1.39, df =1,24, p=0.238), nor on change in YBOCS, Ham-A, Ham-D or NIMH scales from beginning to last evaluation carried forward. These findings suggest that clonazepam is not effective as monotherapy in treating OCD. Its effectiveness in specific subgroups of OCD patients with co-morbid anxiety disorders or as an augmentation strategy added to SSRIs remains to be determined.     

Low doses of clonazepam in the treatment of panic disorder

In order to assess the efficacy of a high-potency benzodiazepine in the treatment of panic disorder, an open trial was conducted with clonazepam. Clonazepam was administered in relatively low doses and, after four weeks, was shown to be effective in reducing the number of panic attacks and associated features of the disorder.     

Successful use of clonazepam in patients with treatment-resistant panic disorder

Ten cases are presented--two in detail--in which clonazepam was used successfully in patients with treatment-resistant panic disorder with or without agoraphobia. Seven of 10 patients who had been resistant to standard pharmacological treatments of panic attacks and agoraphobia achieved cessation of their attacks while three had mild to moderate symptom persistence. These data underscore other reports of clonazepam's usefulness in the treatment of panic disorder. Clinical use of clonazepam is discussed.