The safety of switching rapidly from tricyclic antidepressants to monoamine oxidase inhibitors.

Monoamine oxidase inhibitors (MAOIs) are increasingly used for patients who do not respond to an initial trial of tricyclic antidepressants (TCAs). Although there are insufficient data documenting the optimal manner for switching a patient from a TCA to an MAOI, standard references advise a drug-free interval of at least 1 week. In clinical practice, however, such a delay may be difficult to observe. In order to explore the safety of a more rapid switch from TCA to MAOI therapy, we survey members of our department (Columbia University) as to their experience with different methods of switching patients from TCAs to MAOIs. Thirty-three respondents reported having switched an estimated 432 patients over the course of 3 years, with 178 patients switched within 4 days of discontinuing TCA therapy, including 63 who had the MAOI added while still being tapered from the TCA. More experienced psychiatrists tended to be less conservative, some using time intervals of 4 days or less. No adverse reactions were reported, including hypertensive and hyperpyrexic crises. This retrospective survey and an accompanying review of the literature suggest that the recommended drug-free interval of a week or more when switching patients from TCAs to MAOIs may be overly conservative.