Moclobemide is a reversible inhibitor of monoamine oxidase-A (MAO-A) with IC50 value of 10μM [1].

Moclobemide is a prototype of RIMA agents. It is found to possess antidepressant efficacy with less risk of fatal side-effects like hypertensive crisis. Moclobemide shows a weak but specific inhibition of MAO-A in the in vitro assay using rat brain homogenates. The IC50 values of MAO-A and MAO-B in the assay are 6mM and 1000mM, respectively. In ex vivo animal experiments, moclobemide produces an inhibition of 80% in the brain and liver. Additionally, the long-term administration of high doses of moclobemide is found to down-regulate β-adrenoceptors and increase the agonist binding affinity of α1-adrenoceptors. Moreover, moclobemide is rapidly and almost completely absorbed after oral administration. The bioavailability of moclobemide is about 50% after a single administration of 100 mg [2].

References:
[1] Pisani L, Barletta M, Soto-Otero R, Nicolotti O, Mendez-Alvarez E, Catto M, Introcaso A, Stefanachi A, Cellamare S, Altomare C, Carotti A. Discovery, biological evaluation, and structure-activity and -selectivity relationships of 6'-substituted (E)-2-(benzofuran-3(2H)-ylidene)-N-methylacetamides, a novel class of potent and selective monoamine oxidase inhibitors. J Med Chem. 2013 Mar 28;56(6):2651-64.
[2] Nair NP, Ahmed SK, Kin NM. Biochemistry and pharmacology of reversible inhibitors of MAO-A agents: focus on moclobemide. J Psychiatry Neurosci. 1993 Nov;18(5):214-25.