MAOIs Flashcards
What condition are MAOIs considered more effective for? What are the three features of that disease?
Atypical depression. Characterized by hypersomnia, increased appetite and increased sensitivity to interpersonal rejection.
What is one MAOI that does not require dietary restrictions?
Selegiline (EMSAM patch) is an MAOI used to treat depression that does not require following the dietary restrictions when used in low dosages. However, decongestants, opiates (Demerol), and serotonergic drugs must still be avoided.
What is the first step when you suspect serotonin syndrome?
Discontinue medication. You can also try calcium channel blockers (oral nifedipine). If carefully monitored, you can try chlorpromazine or phentolamine.
What is the mechanism of Monoamine oxidase inhibitors (MAOIs)?
MAOIs prevent the inactivation of biogenic amines such as NE, serotonin, DA and tyramine (an intermediate in the conversion of tyrosine to NE). By irreversibly inhibiting the enzymes MAO-A and MAO-B, MAOIs increase the number of neurotransmitters available in synapses.
What are the differences between MAO-A and MAO-B?
MAO-A preferentially deactivates serotonin. MAO-B preferentially deactivates NE/EPI. Both types act on DA and tyramine.
Why are MAOIs not used as first line agents?
Because of the increased safety and tolerability of newer agents.
What are MAOIs considered very effective for?
Certain types of refractory depression and in refractory panic/anxiety disorder
What are the three main types of MAOIs?
Phenelzine (Nardil)
Tranylcypromine (Parnate)
Isocarboxazid (Marplan)
What are the two most important side effects of MAOIs?
Serotonin syndrome and Hypertensive crisis.
What causes serotonin syndrome?
Occurs when SSRIs and MAOIs are taken together or if other drugs cause increased serotonin levels.
What are the symptoms of serotonin syndrome?
Initially characterized by lethargy, restlessness, confusion, flushing, diaphoresis, tremor, and myoclonic jerks. May progress to hyperthermia, hypertonicity, rhabdomyolysis, renal failure, convulsions, coma and death.
When switching antidepressant medications, what should you do to avoid serotonin syndrome?
Wait at least 2 weeks before switching from SSRI to MAOI, and at least 5-6 weeks with fluoxetine.
What is the cause of Hypertensive crisis?
Risk when MAOIs are taken with tyramine-rich foods or sympathomimetics. Foods with tyramine (red wine, cheese, chicken liver, fava beans, cured meats) cause a buildup of stored catecholamines. In addition to markedly elevated BP, this is also characterized by HA, sweating, nausea and vomiting, photophobia, autonomic instability, chest pain, arrhythmias, and death.
What is one thing to remember when prescribing MAOIs?
Start low and go slow! (low doses that are increased slowly)
What are other side effects of MAOIs?
Orthostatic hypotension (most common), Drowsiness, Weight gain, Sexual dysfunction, Dry mouth, Sleep dysfunction, Rarely there is liver toxicity, seizures and edema. People with pyridoxine deficiency can have paresthesias, treated with B6.
