Reversible inhibitor of monoamine oxidase A

Skeletal formula of moclobemide, the prototypical RIMA.

Ribbon diagram of a monomer of human MAO-A, with FAD and clorgiline bound, oriented as if attached to the outer membrane of a mitochondrion. From PDB 2BXS.

Reversible inhibitors of monoamine oxidase A (RIMAs) are a class of drugs which selectively and reversibly inhibit the enzyme monoamine oxidase A (MAO-A). They are used clinically in the treatment of depression and dysthymia, though they have not gained widespread market share due to limited efficacy relative to other antidepressants.^{[citation needed]} Because of their reversibility and selectivity, RIMAs are safer than the older monoamine oxidase inhibitors (MAOIs) like phenelzine and tranylcypromine.

RIMAs are displaced from MAO-A in the presence of tyramine,^[1] rather than inhibiting its breakdown in the liver as general MAOIs do. Additionally, MAO-B remains free and continues to metabolize tyramine in the stomach, although this is less significant than the liver action. Thus, RIMAs are unlikely to elicit tyramine-mediated hypertensive crisis, and a special diet does not need to be so strictly adhered to, although eating excessively large amounts of tyramine-containing foods is still not advisable.

While safer than general MAOIs, RIMAs still have highly dangerous and sometimes fatal interactions with many common drugs; in particular, they can cause serotonin syndrome or hypertensive crisis when combined with almost any antidepressant or stimulant, common migraine medications, certain herbs, or even most cold medicines (including decongestants, antihistamines, and cough syrup).^{[citation needed]}

List of RIMAs

See also

• Monoamine oxidase inhibitor

References

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