Side effects of MAOIs

Normally, dietary tyramine is broken down in the gastrointestinal tract by MAO and is not absorbed. In the presence of MAOI, however, all of its potent sympathomimetic actions are seen. Other side effects of MAOI include excessive CNS stimulation, orthostatic hypotension, weight gain, and in rare cases hepatotoxicity. Because the monoamine oxidase inhibitors exhibit greater toxicity, yet no greater therapeutic response than other, newer agents, clinical use has been markedly curtailed. The primary use for MAOIs is in the treatment of atypical depressions, eg, those associated with increased appetite, phobic anxiety, hypersomnolence, and fatigues, but not melancholia (2). 

The common side effects of MAOis include dizziness from orthostatic hypotension, drowsiness, insomnia, palpitations, rapid pulse, and sexual dysfunction. In addition, phenelzine appears to cause weight gain and fluid retention. 

The inhibition of MAO enzymes increases the concentrations of these neurotransmit-ters at storage sites throughout the CNS. Side effects of MAOIs include hypotensive effects from the inhibition of central vasomotor centers and cholinergic effects. 

BETA-BLOCKERS MAOIs t hypotensive effect Additive hypotensive effect. Postural 1 BP is a common side-effect of MAOIs Monitor BP at least weekly until stable. Warn patients to report symptoms of hypotension (light-headedness, dizziness on standing, etc.)... 

Although very strict dietary and concomitant drug restrictions must be observed to prevent hypertensive crises and serotonin syndrome, the most common side effects of MAOI/fricyclic or tetracyclic combinations may be weight gain and orthostatic hypotention... 

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