Tyramine pressor response with moclobemide--a reversible monoamine oxidase inhibitor

Moclobemide is a reversible, short-acting monoamine oxidase inhibitor (MAO1), specific for MAO A. To study moclobemide effects on the tyramine pressor response, we gave 12 depressed patients (2 males, 10 females; mean age 47, SD 11 years) an i.v. tyramine test after 7 days drug free. The mean (+/- SD) tyramine dose to raise systolic blood pressure 30 mmHg was 5.6 +/- 2.5 mg. Repeat tyramine testing after 2 weeks of treatment with moclobemide (280 +/- 90 mg/d) showed the tyramine dose required was reduced to 2.5 +/- 1.6 mg (n = 8). The mean (+/- SD) increase in sensitivity to tyramine was 2.9 +/- 1.8. Four patients did not have repeated tyramine tests as testing was discontinued because of tyramine-induced cardiac arrhythmias. Moclobemide seems an effective antidepressant with less tyramine sensitivity than MAOIs in current use.