pronounced as (fen' el zeen)

Brand Name(s): Nardil®, also available generically

Why is this medicine prescribed?

Phenelzine is used to treat depression in people who have not been helped by other medications. Phenelzine is in a class of medications called monoamine oxidase inhibitors (MAOIs). It works by increasing the amounts of certain natural substances that are needed to maintain mental balance.

Are there other uses for this medicine?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

How should this medicine be used?

Phenelzine comes as a tablet to take by mouth. It is usually taken three times a day,. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take phenelzine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Your doctor will probably start you on a low dose of phenelzine and gradually increase your dose. After your symptoms have improved, your doctor will probably gradually decrease your dose. Follow these directions carefully.

Phenelzine controls the symptoms of depression but does not cure the condition. It may take 4 weeks or longer for you to feel the full benefit of phenelzine. Continue to take phenelzine even if you feel well. Do not stop taking phenelzine without talking to your doctor. Your doctor probably will want to decrease your dose gradually. If you suddenly stop taking phenelzine, you may experience withdrawal symptoms such as nightmares, agitation, loss of contact with reality, nausea, vomiting, and weakness.

What special precautions should I follow?

Before taking phenelzine,

  • tell your doctor and pharmacist if you are allergic to phenelzine or any other medications.
  • tell your doctor if you are taking, have recently taken, or plan to take any of the following prescription and non-prescription medications: certain other antidepressants including amitriptyline (Elavil), amoxapine, clomipramine (Anafranil), desipramine (Norpramin), doxepin (Sinequan), imipramine (Tofranil), maprotiline, mirtazapine (Remeron), nortriptyline (Pamelor), protriptyline (Vivactil), and trimipramine (Surmontil);amphetamines such as amphetamine (in Adderall), benzphetamine (Didrex), dextroamphetamine (Dexedrine, Dextrostat, in Adderall), and methamphetamine (Desoxyn);bupropion (Wellbutrin, Zyban); buspirone (BuSpar); caffeine (No-Doz, Quick-Pep, Vivarin); cyclobenzaprine (Flexeril); dexfenfluramine (Redux) (not available in the U.S.); dextromethorphan (Robitussin, others); duloxetine (Cymbalta); epinephrine (Epipen, Primatene Mist); guanethidine (Ismelin) (not available in the U.S.); levodopa (Larodopa, in Sinemet); medications for allergies, cough and cold symptoms, hay fever; anxiety, sinus problems, or weight loss (diet pills, appetite suppressants); medications for seizures such as carbamazepine (Tegretol); narcotic medications for pain; nasal decongestants, including nose drops and sprays; other MAOIs such as isocarboxazid (Marplan); pargyline (not available in the U.S.), procarbazine (Matulane), tranylcypromine (Parnate), and selegiline (Eldepryl, Emsam, Zelapar); meperidine (Demerol); methyldopa (Aldomet); 'pep pills'; sedatives; selective serotonin reuptake inhibitors such as citalopram (Celexa), escitalopram (Lexapro), fluoxetine (Prozac), fluvoxamine (Luvox), paroxetine (Paxil), and sertraline (Zoloft);sleeping pills; tranquilizers; venlafaxine (Effexor); and medications containing alcohol (Nyquil, elixirs, others). Your doctor may tell you not to take phenelzine if you are taking or have recently stopped taking one or more of these medications.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and herbal products you are taking or plan to take. Be sure to mention any of the following: barbiturates such as pentobarbital (Nembutal), phenobarbital (Luminal), and secobarbital (Seconal); beta blockers such as atenolol (Tenormin), labetalol (Normodyne), metoprolol (Lopressor, Toprol XL), nadolol (Corgard), and propranolol (Inderal); doxepin cream (Zonelon), insulin and oral medications for diabetes; and medication for high blood pressure including diuretics ('water pills'), and reserpine (Serpalan). Your doctor may need to change the doses of your medications and monitor you carefully for side effects.
  • you should know that phenelzine may remain in your body for several weeks after you stop taking the medication. During the first few weeks after your treatment ends, tell your doctor and pharmacist that you have recently stopped taking phenelzine before you start taking any new medications.
  • tell your doctor if you are taking any nutritional supplements, especially phenylalanine (DLPA)(contained in aspartame sweetened products such as diet sodas and foods, over-the-counter medications, and some prescription medications), rauwolfia, tyrosine, or tryptophan.
  • tell your doctor if you have or have ever had pheochromocytoma (a tumor on a small gland near the kidneys) or heart or liver disease. Your doctor may tell you not to take phenelzine.
  • tell your doctor if you use street drugs. Also tell your doctor if you have or have ever had high blood pressure; diabetes; seizures; schizophrenia (a mental illness that causes disturbed thinking, loss of interest in life, and strong or unusual emotions); agitation; or hyperactivity or other movement disorders.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking phenelzine, call your doctor.
  • you should know that this medication may make you drowsy. Do not drive a car or operate machinery until you know how this medication affects you.
  • you should know that phenelzine may cause dizziness, lightheadedness, and fainting when you get up too quickly from a lying position. This is more common when you first start taking phenelzine. To avoid this problem, get out of bed slowly, resting your feet on the floor for a few minutes before standing up.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking phenelzine.
  • do not drink alcohol while you are taking phenelzine. Alcohol can make the side effects of phenelzine worse.

What special dietary instructions should I follow?

You may experience a serious reaction if you eat foods that are high in tyramine during your treatment with phenelzine. Tyramine is found in many foods, including meat, poultry, fish, or cheese that has been smoked, aged, improperly stored, or spoiled; certain fruits, vegetables, and beans; alcoholic beverages; and yeast products that have fermented. Your doctor or dietitian will tell you which foods you must avoid completely, and which foods you may eat in small amounts. You should also avoid foods and drinks that contain caffeine during your treatment with phenelzine. Follow these directions carefully. Ask your doctor or dietitian if you have any questions about what you may eat and drink during your treatment.

What should I do if I forget to take a dose?

Take the missed dose as soon as you remember it. However, if it is almost time for your next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What should I do in case of overdose?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at . If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

Symptoms of overdose may include:

  • drowsiness
  • dizziness
  • faintness
  • irritability
  • hyperactivity
  • agitation
  • headache
  • hallucinations (seeing things or hearing voices that do not exist)
  • tightening of the jaw
  • stiffly arched back
  • seizures
  • coma (loss of consciousness for a period of time)
  • fast, irregular pulse
  • chest pain
  • slowed breathing
  • fever
  • sweating
  • cool, clammy skin

What side effects can this medicine cause?

Phenelzine may cause side effects. Tell your doctor if any of the following symptoms are severe or do not go away:

  • drowsiness
  • weakness
  • dizziness
  • dry mouth
  • constipation
  • weight gain
  • decreased sexual ability
  • uncontrollable shaking of any part of the body
  • muscle twitching or jerking

Some side effects can be serious. If you experience any of the following symptoms or those listed in the IMPORTANT WARNING section, call your doctor immediately:

  • headache
  • slow, fast, or pounding heartbeat
  • neck stiffness or soreness
  • chest pain
  • nausea
  • vomiting
  • sweating
  • wide pupils (black circles in the middle of the eyes)
  • eyes more sensitive to light than usual
  • swelling of face, throat, arms, hands, feet, ankles, or lower legs
  • difficulty breathing or swallowing
  • yellowing of the skin or eyes

Phenelzine may cause other side effects. Call your doctor if you experience any unusual problems while you are taking this medication.

What should I know about storage and disposal of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website ( ) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach.

What other information should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will check your blood pressure regularly during your treatment with phenelzine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

subscribe section background