Monoamine Oxidase Inhibitors (MAOI's) (Anti-depressants) Flashcards
What are the 5 drugs of MAOI’s?
Phenelzine, Isocarboxazid, Tranylcypromine, Moclobemide (not available in US), and Selegiline (transdermal patch).
What’s important about the PK of Hydrazine?
Even though its mainly MAO oxidation metabolism, and acetylation is the minor pathway, slow acelytators (which is more than 50% of asians and whites) will have elevated plasma levels of MAOIs. Its oral.
Tranykcypromide and moclobemide PK?
Oral, and hepatically oxidized.
Selegiline PK?
Transdermal, it bypasses liver and gut to increase bioavail, 2B6 hepatic metabolism, oral half life 10 hrs, transdermal 18-25 hours.
General mech of action of MAOIs?
Non selective, irreversible inhibitors of MAO-A and MAO-B, with the exception of moclobemide which is a short acting reversible inhibitor specific for MAO-A.
What happens if you inhibit MAO?
Inhibition of the breakdown of serotonin, norepi and dopamine (all monoamines) so there are more available to be stored in secretory vescicles.
Alternate use for Selegiline?
It’s selectivity for MAO-B and lower oral doses are used for Parkinson disease.
When would we use MAOIs?
When other depression meds are unresonsive. It’s as effective as TCAs.
Class AE’s of MAOI’s?
Orthostatic Hypotension, weight gain, sex dysfunction, agitation, restlessness and insomnia. Withdrawal syndrome including delirium and psychosis, excitement and confusion.
When are MAOI’s contraindicated?
CV diseases including HTN, cerebrovascular defect, history of headache, hepatic disease or abnormal liver function test, and pheochromocytoma.
Drug/Food interactions with MAOIs?
Foods that contain TYRAMINE like aged cheese, fermented products, etc, if elevated levels it acts to release norepi. It can cause HTN crisis. Serotonin syndrome, seizures,with any drugs that increase MAOI levels. 5-HT1D agonists that are metabolized by MAOs. Drugs like sumatriptan, rizatriptan, zolmitriptan and almotriptan are problematic.
CIs of MAOIs?
Other antidepressants, including other MAOIs, tyramine containing foods, dextromethopran, methadone, propoxyphene, tramadol, carbamazepine, oxocarbazepine, sympathomimetics, cyclobenzaprine, ethanol, general anasthesia, local anesthesia that contains sympathomimetic vasoconstrictor.
Overdose signs and symptoms of MAOIs? Tx
Related to adrenergic and serotonergic excess, leads to cardiovascular compromise, shock, hyperthermia, obtunded consciousness, seizures. Tx is supportive and symptomatic.
