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Generic name: phenelzine [ FEN-el-zeen ]
Brand name: Nardil
Dosage form: oral tablet (15 mg)
Drug class: Monoamine oxidase inhibitors

Medically reviewed by on Feb 21, 2023. Written by Cerner Multum.

What is phenelzine?

Phenelzine is a monoamine oxidase inhibitor (MAOI) that is used to treat symptoms of atypical depression in adults when other medicines have not been effective.

Phenelzine is not for treating severe depression or bipolar disorder (manic depression).

Phenelzine may also be used for purposes not listed in this medication guide.

Phenelzine side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, panic attacks, trouble sleeping, or if you feel impulsive, irritable, agitated, hostile, aggressive, restless, hyperactive (mentally or physically), more depressed, or have thoughts about suicide or hurting yourself.

Phenelzine may cause serious side effects. Call your doctor at once if you have:

  • sudden and severe headache, neck pain or stiffness;

  • pounding heartbeats or fluttering in your chest;

  • fast or slow heartbeats;

  • chest pain;

  • a light-headed feeling, like you might pass out;

  • sweating (sometimes with fever and sometimes with cold, clammy skin);

  • nausea, vomiting; or

  • dilated pupils (your eyes may be more sensitive to light).

Common side effects of phenelzine may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


Some young people have thoughts about suicide when first taking an antidepressant. Stay alert to changes in your mood or symptoms. Report any new or worsening symptoms to your doctor.

There are many other drugs, foods, and beverages that can cause dangerously high blood pressure if you take them together with phenelzine. Tell your doctor about all your current medicines and any you start or stop using. Avoid drinking alcohol, and learn about the foods you should avoid.

Symptoms of dangerously high blood pressure include: a sudden and severe headache, nausea, vomiting, fever, cold sweat, dilated pupils, light sensitivity, fast or pounding heartbeats, neck stiffness, weakness, or problems with vision or speech.

Before taking this medicine

You should not use phenelzine if you are allergic to it, or if you have:

  • pheochromocytoma (tumor of the adrenal gland).

  • congestive heart failure;

  • severe kidney disease; or

  • a history of liver problems or abnormal liver function tests.

A dangerous drug interaction can occur between phenelzine and certain other medicines you use within 14 days before or after taking phenelzine. Your doctor may change your treatment plan if you need to use any of these medicines, including:

This is not a complete list and there may be other medicines you should not take while you are taking phenelzine.

Tell your doctor if you have ever had:

Some young people have thoughts about suicide when first taking an antidepressant. Your doctor should check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Tell your doctor if you are pregnant or breastfeeding.

Phenelzine is not approved for use by anyone younger than 18 years old.

How should I take phenelzine?

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Your blood pressure will need to be checked often.

You may need to stop using phenelzine for a short time before any type of surgery or medical procedure. Tell any doctor who treats you that you take phenelzine.

It may take a few weeks before you receive the full benefit of taking phenelzine. Your doctor will determine how long to treat you with phenelzine.

Do not stop using phenelzine suddenly, or you could have unpleasant withdrawal symptoms. Ask your doctor how to safely stop using this medicine.

Store at room temperature away from moisture and heat.

Phenelzine dosing information

Usual Adult Dose for Depression:

Early phase treatment:
-Initial dose: 15 mg orally 3 times a day
-Dose titration: Increase to at least 60 mg per day fairly rapidly, as tolerated
-Maximum dose: 90 mg/day

-Maintenance dose may be as low as 15 mg orally once a day or 15 mg orally every other day
-Duration of therapy: As long as required

-This drug should rarely be the first antidepressant used; it is more suitable for patients unresponsive to more commonly used medications.
-This drug is effective in depressed patients characterized as atypical, nonendogenous, or neurotic, who often have mixed anxiety and depression and phobic or hypochondriacal features.
-Evidence of usefulness in severely depressed patients with endogenous features is less conclusive.
-Clinical response may not be seen until at least 4 weeks at 60 mg per day dosing
-After maximal benefit is achieved, reduce dose slowly over several weeks.

Use: Treatment of clinically characterized atypical, nonendogenous, or neurotic depression, especially in patients who have failed first-line treatments

What happens if I miss a dose?

Take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222. Overdose symptoms may include feeling drowsy or dizzy, severe headache, neck pain or stiffness, hallucinations, shallow breathing, fast and uneven heart rate, cold sweats, feeling like you might pass out, or seizure (convulsions).

What should I avoid while taking phenelzine?

Do not drink alcohol. Dangerous side effects could occur.

You must not eat certain foods, including:

  • air dried, aged, smoked, or fermented meats, including sausage, pepperoni, Lebanon bologna, or salami;

  • beer, wine, reduced-alcohol or alcohol-free beer or wine;

  • pickled herring;

  • aged cheeses, including blue, boursault, brie, camembert, cheddar, gruyere, mozzarella, parmesan, Romano, Roquefort, and Swiss;

  • moldy or improperly stored meat, fish, poultry, or liver;

  • soy sauce, miso soup, bean curd, fava beans;

  • sauerkraut;

  • yogurt;

  • yeast extracts, Marmite; or

  • excessive amounts of chocolate or caffeine.

Eating these foods while you are taking phenelzine can raise your blood pressure to dangerous levels, causing life-threatening side effects. Also avoid these foods for 2 weeks after you stop taking phenelzine.

Phenelzine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

What other drugs will affect phenelzine?

When you start or stop taking phenelzine, your doctor may need to adjust the doses of any other medicines you take on a regular basis.

There are many other drugs that can cause serious medical problems if you take them together with phenelzine. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide. Tell your doctor about all your current medicines and any medicine you start or stop using.

Frequently asked questions

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.