Monoamine Oxidase Inhibitors (MAOIs, MAOI)

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What are monoamine oxidase inhibitors (MAOIs)?

MAOIs were the first class of antidepressants to be developed. They fell out of favor because of concerns about interactions with certain foods and numerous drug interactions. MAOIs elevate the levels of norepinephrine, serotonin, and dopamine by inhibiting an enzyme called monoamine oxidase. Monoamine oxidase breaks down norepinephrine, serotonin, and dopamine. When monoamine oxidase is inhibited, norepinephrine, serotonin, and dopamine are not broken down, increasing the concentration of all three neurotransmitters in the brain. They are also used for treating Parkinson's.

What are examples of MAOIs available in the US?

Examples of oral MAOIs include:

  • rasagiline (Azilect),
  • selegiline (Eldepryl, Zelapar),
  • isocarboxazid (Marplan),
  • phenelzine (Nardil), and
  • tranylcypromine (Parnate).

Selegiline is also available in a topical patch form called Emsam.

What are the side effects of MAOIs?

Since MAOIs work in brain and affect neurotransmitters, they have many side effects. Side effects of MAOIs are:

MAOIs also carry boxed warnings of suicidal thinking and suicidal behavior in children, adolescents, and young adults.

What drugs interact with MAOIs?

MAO inhibitors should be avoided with other antidepressants such as paroxetine fluoxetine, amitriptyline, nortriptyline, bupropion; pain medications like methadone, tramadol, and meperidine; dextromethorphan, St. Johns Wort, cyclobenzaprine, and mirtazapine. Such combinations lead to high serotonin levels which may lead to confusion, high blood pressure, tremor, hyperactivity, coma, and death.

Medically Reviewed by a Doctor on 7/2/2014



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