The mechanism of action of moclobemide involves the selective, reversible inhibition of MAO-A. This inhibition leads to a decrease in the metabolism and destruction of monoamines in the neurotransmitters. This results in an increase in the monoamines, relieving depressive symptoms.
Moclobemide belongs to a class of MAOI antidepressants known as reversible inhibitors of monoamine oxidase type-A (RIMAs). The primary role of monoamine oxidase MAO lies in the metabolism of and regulation of the levels of monoamines (serotonin, norepinephrine, and dopamine). Within neurons, MAO appears to regulate the levels of monoamines released upon synaptic firing. Since depression is associated with low levels of monoamines, the inhibition of MAO serves to ease depressive symptoms. RIMAs demonstrate transient inhibition of the substrate binding site of MAO-A as well as competitive displacement from this site by bioamines. The RIMAs are distinguished from the older monoamine oxidase inhibitors (MAOIs) by their selectivity and reversibility.
Moclobemide is almost completely metabolized in the liver by Cytochrome P450 2C19 and 2D6.
LD50 (mouse) is 730mg/kg and LD50 (rat) is 1, 300mg/kg. Signs of toxicity include hypertension, drowsiness, dizziness, confusion, tremors, headache, agitation, muscle rigidity and seizures.