A Cochrane review includes 5 RCTs with a total of 884 people with generalized anxiety disorder (GAD). As regards the number of patients showing a response, hydroxyzine was more effective than placebo (OR 0.30, 95% CI 0.15 to 0.58; 4 trials, n=417) and it was also tolerable (OR 1.49, 95% CI 0.92 to 2.40; 4 trials, n=584). Hydroxyzine was as efficacious as other anxiolytic agents, chloridiazepoxide (OR 0.75, 95% CI 0.35 to 1.62; 1 trial, n=106) and buspirone (OR 0.76, 95% CI 0.40 to 1.42; 1 trial, n=163). There was no difference between hydroxyzine and benzodiazepines in side effects (OR 1.07, 95% CI 0.60 to 1.93; 2 trials, n=327).
Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment), indirectness of evidence (differences in studied outcomes) and imprecise results (limited study size for each comparison).