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Potentiation of the pressor effect of intravenously administered tyramine during moclobemide treatment
Author(s) -
Zimmer R.,
Fischbach R.,
Breuel H. P.
Publication year - 1990
Publication title -
acta psychiatrica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.849
H-Index - 146
eISSN - 1600-0447
pISSN - 0001-690X
DOI - 10.1111/j.1600-0447.1990.tb05340.x
Subject(s) - moclobemide , placebo , tyramine , medicine , pharmacology , anesthesia , antidepressant , alternative medicine , pathology , hippocampus
Potentiation of the pressor effect of tyramine (TYR) by intravenous (i. v.) injection during moclobemide treatment was investigated in healthy volunteers and in depressed patients. The TYR sensitivity factor (TSF) is calculated as the ratio between the dose of TYR required to raise systolic blood pressure by 30 mmHg (TYR 30) without drug and that required with drug. After single‐dose administration the TYR 30 for 100 mg moclobemide was 1.8 mg, and those for moclobemide 200 and 300 mg 1.6, compared with 3.2 for placebo, giving corresponding TSF values of 1.7, 2.0 and 2.0 respectively. Twenty‐four hours after moclobemide intake, only the 300‐mg dose yielded a mean TYR 30 value significantly different from placebo. The same doses of moclobemide given 3 times daily for 1 week resulted in a peak TSF of 2.0 with 100 mg, 2.9 with 200 mg and 3.3 with 300 mg (the latter dose being higher than normally recommended for 3 times daily administration). Nevertheless, 24 h after the last 300‐mg dose the TSF was 1.2, similar to that of a single dose. In a study of 17 depressed female patients treated with moclobemide 100 mg 3 times daily, no relevant differences were found in TSF values from those of the volunteers. The authors conclude that, because of the short‐lasting, reversible and selective MAO‐A‐inhibiting effect of moclobemide, there is no marked interaction with tyramine given by i. v. injection. No relevant difference was seen between depressed patients and healthy volunteers in the tyramine pressor effect. Although the potentiation of the pressor effect was time‐ and dose‐dependent, only a slight difference between 200 and 300 mg 3 times daily was observed, indicating that, in the event of overdosage, no major further increase in the potentiation of the pressor effect of tyramine is likely.