What Is an MAOI?

Medically Reviewed

MAOIs were the first type of antidepressant developed, and became widely used in the 1950s.

A monoamine oxidase inhibitor, or MAOI, is a type of antidepressant drug.

In addition to treating depression, MAOIs are sometimes used to treat such conditions as:

MAOIs balance the level of certain chemicals in the brain by inhibiting the enzyme known as monoamine oxidase.

The following medicines are examples of MAOIs:

MAOIs were the first type of antidepressant developed, and became widely used in the 1950s.

Today, a doctor typically prescribes an MAOI only when other antidepressants fail, because newer drugs are often more effective and have fewer side effects.

MAOI Side Effects

There is a risk of serious side effects, especially when MAOIs are combined with certain food or drugs.

Some side effects of MAOIs include:

  • Dry mouth
  • Nausea
  • Diarrhea or constipation
  • Drowsiness
  • Headache
  • Insomnia or other sleep disturbance
  • Agitation
  • Skin reactions
  • Dizziness
  • Low blood pressure
  • Involuntary muscle jerks or muscle aches
  • Reduced sexual desire or decreased sexual ability
  • Weight gain
  • Difficulty urinating
  • Tingling sensation of the skin

MAOIs — like all antidepressants — also carry a black-box warning about the potential for suicidal thoughts and behaviors.

In short-term studies, antidepressants increased the risk of suicidal tendencies in some children and young adults with depression or psychiatric disorders.

MAOIs and Drug Interactions

MAOIs can cause serious reactions if you take them with certain other drugs.

Be sure to tell your doctor and pharmacist all the medications you're taking before you take an MAOI.

This includes prescriptions and over-the-counter medications, vitamins and other dietary supplements (nutritional shakes, protein powders, etc.), herbal remedies, and illegal or recreational drugs.


Certain foods and drinks can cause dangerous reactions if they're taken with an MAOI.

Your physician will probably tell you to avoid foods that contain high levels of tyramine, dopamine, and tryptophan.

Some restricted foods may include:

  • Aged cheeses
  • Yogurt
  • Cured meats and certain other meat products
  • Fermented sausages such as pepperoni, salami, and bologna
  • Beef or chicken liver
  • Anchovies
  • Caviar
  • Herring
  • Shrimp paste
  • Draft beer and red wine
  • Certain liqueurs
  • Fermented soy products, such as soy sauce, miso, or tofu
  • Sauerkraut
  • Certain fruits, such as bananas, raspberries, dried fruits, or overripe fruits
  • Fava beans
  • Chocolates
  • Caffeinated beverages, such as coffee, tea, or cola

Talk to your doctor about all dietary restrictions before taking an MAOI, and make sure you understand which foods and drinks to avoid.

MAOIs and Pregnancy

Since there is so little known about the effects of MAOIs on a developing baby, doctors generally avoid prescribing them during pregnancy or breastfeeding.

Also, MAOIs may interact with other medications that you may need during labor and delivery.

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