Safety of Hypericum extract in mildly to moderately depressed outpatients: A review based on data from three randomized, placebo-controlled trials

Rationale: Hypericum extracts have been regarded as antidepressant drugs wihtout specific side effects by patients, medical professionals and researchers alike. Recently there has been discussion about potential interactions between St. Johnʹs wort and other drugs. Objectives: To investigate the tolerability of Hypericum extract by comparing adverse event rates observed during clinical trials with the herbal drug to those observed under placebo and synthetic antidepressants. Methods: A data review was performed based on the original data of three double-blind, randomised multicenter trials, during which 594 out-patients suffering from mild to moderate depression according to DSM-IV criteria received 3 × 300 mg/day Hypericum extract (WS® 5570, WS® 5572, WS® 5573) or placebo over a double-blind treatment period of 6 weeks. For the polled data from the three trials, the risk ratios and risk differences versus placebo for single and grouped adverse events were determined along with their 95% confidence intervals. The data were inspected for relevant differences between Hypericum extract and placebo and were compared to trials involving the adminstration of several synthetic antidepressants. Results: For the polled data of the three trials, the percentage of patients with any adverse events under Hypericum extract exposition was comparable to placebo. The drug was also found to be devoid of effects of sedation, anticholinergic reactions, gastrointestinal disturbances and sexual dysfunction often found in patients treated with tricyclic antidepressants or selective serotonin reuptake inhibitors. Conclusion: The analysis did not reveal any specific effects of Hypericum extract.