Moclobemide in social phobia : A controlled dose-response trial

Although the monoamine oxidase inhibitor phenelzine has proven efficacious in social phobia, the risk of hypertensive crises has reduced its acceptability. The reversible monoamine oxidase inhibitor moclobemide has less potential for such reactions, but its efficacy in this disorder remains unproven. A double-blind, placebo-controlled study was undertaken to assess the efficacy and safety of fixed doses of moclobemide. After a 1-week placebo run-in, subjects with social phobia were randomly assigned to placebo or one of five doses (75 mg, 150 mg, 300 mg, 600 mg, or 900 mg daily) of moclobemide for 12 weeks. Although a trend toward greater efficacy of higher doses of moclobemide was observed at 8 weeks, no differences in response to various doses of the drug and placebo were observed at 12 weeks. At 12 weeks, 35% of subjects on 900 mg of moclobemide and 33% of those on placebo were at least much improved. Moclobemide was well tolerated, insomnia being the only dose-related adverse event observed with the drug. In this dose-response trial, moclobemide did not demonstrate efficacy at 12 weeks. Some other controlled studies have found moclobemide and brofaromine, another reversible monoamine oxidase inhibitor, efficacious in social phobia. Possible reasons for inconsistent findings are discussed.