• Basic Info
• Top Questions
• Interactions

What is phenelzine?
Phenelzine is a monoamine oxidase inhibitor (MAOI) that works by increasing the levels of certain chemicals in the brain. Phenelzine is used to treat symptoms of depression that may include feelings of sadness, fear, anxiety, or worry about physical health (hypochondria). This medication is usually given after other anti-depressants have been tried without successful treatment of symptoms. Phenelzine is not for treating severe depression or bipolar disorder (manic depression). Phenelzine may also be used for purposes other than those listed in this medication guide.

Back to Top

What are the possible side effects of phenelzine?

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

Call your doctor at once if you have any new or worsening symptoms 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.

Stop using phenelzine and call your doctor at once if you have any of these serious side effects:

• sudden and severe headache, rapid heartbeat, stiffness in your neck, nausea, vomiting, cold sweat, sweating, vision problems, sensitivity to light;

• chest pain, fast or slow heart rate;

• swelling, rapid weight gain;

• agitation, unusual thoughts or behavior; or

• feeling light-headed, fainting.

Less serious side effects may include:

• dizziness;

• feeling weak or drowsy;

• sleep problems (insomnia);

• constipation, upset stomach;

• dry mouth, decreased urination; or

• impotence, difficulty having an orgasm.

This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect.

Back to Top

How should I take phenelzine?
Take this medication exactly as it was prescribed for you. Do not take the medication in larger amounts, or take it for longer than recommended by your doctor. Follow the instructions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results from this medication. Take each dose with a full glass of water. To be sure this medication is not causing harmful effects, your blood pressure will need to be tested on a regular basis. Do not miss any scheduled visits to your doctor.

Back to Top

What is the most important information I should know about phenelzine?
There are many other medicines that can cause serious or life-threatening medical problems if you take them together with phenelzine. Do not take phenelzine before telling your doctor about all other prescription and over-the-counter medications you use, including vitamins, minerals, and herbal products. Keep a list with you of all the medicines you use and show this list to any doctor, dentist, or other healthcare provider who treats you. You may have thoughts about suicide when you first start taking an antidepressant, especially if you are younger than 24 years old. Your doctor will need to check you at regular visits for at least the first 12 weeks of treatment.

Back to Top

What happens if I miss a dose?
Take the missed dose as soon as you remember. However, if it is almost time for your next regularly scheduled dose, skip the missed dose and take only the next one as directed. Do not take a double dose of this medication.

Back to Top

What other drugs will affect phenelzine?
There are many other medicines that can cause serious or life-threatening medical problems if you take them together with phenelzine. Do not take phenelzine before telling your doctor about all other prescription and over-the-counter medications you use. This includes vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start using a new medication without telling your doctor. Keep a list with you of all the medicines you use and show this list to any doctor, dentist, or other healthcare provider who treats you.

Back to Top

Can I take this if I am pregnant or trying to get pregnant or if I am breastfeeding?

Phenelzine has been assigned to pregnancy category C by the FDA. Animal studies have revealed evidence of embryolethality and growth retardation. There are no controlled data in human pregnancy. Phenelzine is only recommended for use during pregnancy when there are no alternatives and benefit outweighs risk.

There are no data on the excretion of phenelzine into human milk. The manufacturer recommends that a decision be made whether to discontinue nursing or to discontinue phenelzine, taking into account the importance of the drug to the mother.

Back to Top

What happens if I overdose?
Seek emergency medical attention if you think you have used too much of this medicine. 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).

Back to Top

What should I discuss with my doctor before taking phenelzine?
Do not use this medication if you have used another MAOI such as isocarboxazid (Marplan), rasagiline (Azilect), selegiline (Eldepryl, Emsam), or tranylcypromine (Parnate) within the past 14 days. Serious, life-threatening side effects can occur if you take phenelzine before another MAOI has cleared from your body. Do not take this medication if you are allergic to phenelzine, or if you have: pheochromocytoma (tumor of the adrenal gland); congestive heart failure; a history of liver problems; or

Back to Top

Can I stop taking the medication if I feel better?
As a general rule, you should always take your medications exactly as prescribed and do not change the dosage or stop taking the medication without first discussing it with your healthcare provider.

Back to Top

I am on so many medications; do I have to take them all?
This is called polypharmacy—many different medications being used at the same time by one person. Sometimes, being on multiple medications is acceptable and appropriate but at other times it may be problematic. If you are receiving your medications from multiple physicians you need to ensure that they all know what medications you are taking. The best way to do this is to make a list of all the medications you are currently using, including all nutritional supplements, homeopathic remedies, vitamins and over-the-counter drugs (if possible, also include all the diseases you have been diagnosed with). Give a copy to every doctor who takes care of you so they have it on file, this way they can avoid duplicating medications and perhaps even try to consolidate some. After every doctor's visit remember to update the list accordingly. Also, as much as you possibly can, try to use the same pharmacy to fill all your prescriptions, this way any potential drug interactions can be caught and averted.

Back to Top