RIMAs, or reversible inhibitors of monoamine oxidase A, are a class of depression treatment drugs that stop the breakdown of serotonin, dopamine, and norepinephrine. They “inhibit” the enzyme monoamine oxidase A, which breaks down these neurotransmitters. It is believed that this enzyme could be overactive in those with depression.
RIMAs vs. MAOIs
RIMAs are mostly considered to be safer and preferred over monoamine oxidase inhibitors (MAOIs). MAOIs are the “original” iteration of depression medications that stop the breakdown of dopamine by inhibiting monoamine oxidase.
Generally, RIMAs potentially have fewer side effects, less unfavorable interaction with other drugs, and overall higher tolerability than their MAOI predecessors. This could differ patient to patient, depending on medical history and individual biology.
Furthermore, RIMAs do not appear to carry the same level of risk regarding dietary tyramine that MAOIs do. MAOIs inhibit MAO, which helps to break down tyramine in the body. If you take an MAOI and then eat a lot of tyramine, it could lead to dangerously high blood pressure.
Having to restrict tyramine from your diet is more challenging than you may think (tyramine’s in a lot of foods, from cheese to citrus). This is one of the reasons patients often either dislike or have to discontinue treatment with MAOIs.
Also, discontinuation of treatment with RIMAs is not a difficult process, which can sometimes be the case with other depression medications.
RIMAs provide a reversible inhibition of monoamine oxidase A, with brain levels returning to normal 24 hours after taking the drug.
– Lotufo-Neto, F., Trivedi, M. & Thase, M. Meta-Analysis of the Reversible Inhibitors of Monoamine Oxidase Type A Moclobemide and Brofaromine for the Treatment of Depression. Neuropsychopharmacol 20, 226–247 (1999). https://doi.org/10.1016/S0893-133X(98)00075-X https://www.nature.com/articles/1395258
– Amrein R, Hetzel W, Stabl M, Schmid-Burgk W. RIMA: a safe concept in the treatment of depression with moclobemide. Can J Psychiatry. 1992;37 Suppl 1:7-11. https://pubmed.ncbi.nlm.nih.gov/1394030/
– Rybakowski, Janusz K., et al. “Moclobemide-a Reversible Inhibitor of Monoamine Oxidase-A.” Psychiatric Annals, 6 Nov. 2014. https://journals.healio.com/doi/10.3928/00485713-20141106-05
– Fowler JS, Logan J, Azzaro AJ, et al. Reversible inhibitors of monoamine oxidase-A (RIMAs): robust, reversible inhibition of human brain MAO-A by CX157. Neuropsychopharmacology. 2010;35(3):623-631. doi:10.1038/npp.2009.167 https://pubmed.ncbi.nlm.nih.gov/19890267/