Your doc recommended an antidepressant. Knowing nothing about them, you talked it over with a friend. She said she takes a monoamine oxidase inhibitor. “Huh?”  Not to worry, got you covered. Let’s learn about them…

Now, it’s vitally important to understand that the MAOIs have significant dietary restrictions. In fact, ignoring these restrictions can be fatal.

We began our series on antidepressants with a bit of history. And we moved on to discuss the tricyclic and tetracyclic antidepressants. Be sure to read part one

In part two we’re going to review the monoamine oxidase inhibitors (MAOIs). And we just might learn a few more things along the way.

Monoamine oxidase inhibitors

The monoamine oxidase inhibitors (MAOIs) are an older class of antidepressants. Some of the better known MAOIs are isocarboxazid (Marplan), phenelzine (Nardil), tranylcypromine (Parnate), moclobemide (Aurorix), and selegiline (Emsam).

What is monoamine oxidase?

First the monoamine part. In part one we established that neurotransmitters facilitate the jump of electricity from one neuron (nerve cell) to another – allowing them to communicate. Well, neurotransmitters are categorized. And the neurotransmitters dopamine, norepinephrine, and epinephrine are known as monoamines.

Monoamine oxidases are a family of enzymes that induce the oxidation of monoamines (well that makes sense). And any sort of monoamine oxidase imbalance can cause emotional/mental issues.

How do MAOIs work?

The monoamine oxidase inhibitors, indeed, inhibit monoamine oxidase. This prevents the breakdown of the monoamine neurotransmitters, increasing their availability.

Now, it’s vitally important to understand that the MAOIs have significant dietary restrictions. In fact, ignoring these restrictions can be fatal.

When foods with tyramine are ingested, a hypertensive crisis may result. When foods containing tryptophan are consumed, something known as hyperserotonemia (excessive serotonin levels) may occur.

More on this, as well as drug interaction issues, downstairs.

Why would I take an MAOI?

The primary reason one would take an MAOI would be to address treatment resistant depression. MAOIs are typically used as a last resort because of the dietary restrictions and drug interaction issues we just discussed.

That said, there’s a fairly new MAOI administered via skin patch – selegiline (Emsam) – that decreases the dangers of dietary interactions. That’s accomplished by the drug being absorbed through the skin, thereby sidestepping the gastrointestinal system.

Moclobemide (Aurorix) is also considered to be safer than the earlier MAOIs; however, it may not work as well.

MAOIs are also used to treat the anxiety disorders, Parkinson’s Disease, and migraine headache.

Any side effects?

MAOI side effects include daytime sleepiness, low blood pressure, dry mouth, diarrhea, edginess, weight gain, reduced sexual desire or difficulty reaching orgasm, and erectile dysfunction.

Other concerns?

Let’s get into the dietary restrictions we discussed earlier. Common foods containing high amounts of tyramine include cheeses, alcoholic beverages, herbal extracts, eggplant, figs, grapes, oranges, pineapples, plums, prunes, raisins, aged meats, fish, poultry, and soy products.

Common foods high in tryptophan include chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sunflower seeds, and peanuts.

It’s important to understand that there are interaction issues with prescription, over-the-counter, and recreational drugs, as well as supplements. The list is longer than both of my arms, so how ’bout we leave it at this: if you’re using an MAOI – any antidepressant – touch base with your physician before taking any drug or supplement.

As with all antidepressants, sudden cessation isn’t such a hot idea. Believe me, you won’t like the outcome.

Finally, The FDA has ordered that all antidepressants carry a Black Box Warning indicating that they are associated with an increased risk of suicidal thinking, feeling, and behavior in children and adolescents. A warning is also given for an increased risk of suicidal symptoms in young adults, ages 18-24.

That’s a wrap

Alrighty then, that’s a wrap on part two of the series. You’ll for sure want to read part three. We’ll discuss the serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), and a few more.

For some helpful info, visit the FDAs Information for Consumers and Patients website.

If you’d like even more help, review the Chipur titles.

Bill White is not a physician and is providing the contents of this article for information purposes only, not to serve as a recommendation. Contact your physician with questions and for advice. 

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