Azapirones versus placebo for panic disorder in adults

Panic disorder is common in the general population. It is often associated with other psychiatric disorders, such as drug dependence, major depression, bipolar disorder, social phobia, specific phobia and generalised anxiety disorder. Azapirones are a class of drugs used as anxiolytics. They are associated with less drowsiness, psychomotor impairment, alcohol potentiation and potential for addiction or abuse than benzodiazepines. However, azapirones are not widely used in the treatment of panic disorder and evidence for their efficacy is unclear. It is important to find out if azapirones are effective and acceptable in the treatment of panic disorder.

To assess the effects of azapirones on panic disorder in adults, specifically:1. to determine the efficacy of azapirones in alleviating symptoms of panic disorder, with or without agoraphobia, in comparison with placebo;2. to review the acceptability of azapirones in panic disorder, with or without agoraphobia, in comparison with placebo; and3. to investigate adverse effects of azapirones in panic disorder with or without agoraphobia, including general prevalence of adverse effects, compared with placebo.

We searched the Cochrane Depression Anxiety and Neurosis Group Trials Specialised Register (CCDANCTR, search date: 10th January 2014), which includes relevant randomised controlled trials from The Cochrane Library (all years), MEDLINE (1950-), EMBASE (1974-), and PsycINFO (1967-).

Randomised controlled trials that compared azapirones with placebo for panic disorder in adults.

Three review authors independently identified studies, assessed trial quality and extracted data. We contacted study authors for additional information.

Three studies involving 170 participants compared the azapirone buspirone with placebo. No study provided enough usable information on our primary efficacy outcome (response). For our primary acceptability outcome, moderate-quality evidence indicated that azapirones had lower acceptability than placebo: risk ratio (RR) for dropouts for any reason 2.13 (95% confidence interval (CI) 1.11 to 4.07; 3 studies, 170 participants. Evidence for secondary efficacy outcomes were of low quality. Results on efficacy between azapirone and placebo in terms of agoraphobia (standardised mean difference (SMD) -0.01, 95% CI -0.56 to 0.53; 1 study, 52 participants), general anxiety (mean difference (MD) -2.20, 95% CI -5.45 to 1.06; 2 studies, 115 participants) and depression (MD -1.80, 95% CI -5.60 to 2.00; 1 study, 52 participants) were uncertain. None of the studies provided information for the assessment of allocation concealment or sequence generation. Conflicts of interest were not explicitly expressed. The risk of attrition bias was rated high for all three studies. Information on adverse effects other than dropouts for any reason was insufficient to include in the analyses.

The efficacy of azapirones is uncertain due to the lack of meta-analysable data for the primary outcome and low-quality evidence for secondary efficacy outcomes. A small amount of moderate-quality evidence suggested that the acceptability of azapirones for panic disorder was lower than for placebo. However, only trials of one azapirone (namely buspirone) were included in this review; this, combined with the small sample size, limits our conclusions. If further research is to be conducted, studies with larger sample sizes, with different azapirones and with less risk of bias are necessary to draw firm conclusions regarding azapirones for panic disorder.