Phenelzine

Pronunciation: (fen-EL-zeen).

Generic name: Phenelzine
Brand names: Nardil, Phenelz, Phenelzine
Drug class: Monoamine Oxidase Inhibitor (MAOI) Antidepressant

Availability and supply rules vary by country

Trade names by country: United States · Canada

What Phenelzine is and how it works

Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.

Mechanism of action: how Phenelzine works

Phenelzine is a non-selective, irreversible inhibitor of monoamine oxidase (MAO) types A and B. By inhibiting MAO, it prevents the breakdown of monoamine neurotransmitters (serotonin, norepinephrine, dopamine), leading to increased synaptic concentrations and enhanced neurotransmission. This mechanism underlies its antidepressant and anxiolytic effects. (1)

What Phenelzine is used for

Phenelzine is a prescription medication used to treat depression, especially when other treatments have not been effective. It belongs to a group of medicines called monoamine oxidase inhibitors (MAOIs), which work by increasing certain natural chemicals in the brain that help maintain mental balance. This medication is typically used for major depressive disorder, particularly with features such as anxiety or atypical symptoms.

Extracted from the clinician-authored database description field (no separate structured indications list was present in the DB record for this medicine).

Before taking Phenelzine

Do not take / not appropriate for

Do not take phenelzine if you are hypersensitive (allergic) to the drug or any of its ingredients. (all countries)
Do not take phenelzine if you have phaeochromocytoma (pheochromocytoma), an adrenal gland tumour. (all countries)
Do not take phenelzine if you have congestive heart failure. (all countries)
Do not take phenelzine if you have severe kidney impairment or kidney disease. (all countries)
Do not take phenelzine if you have a history of liver disease or abnormal liver function tests. (all countries)
Do not take sympathomimetic drugs (including amphetamines, cocaine, methylphenidate, dopamine, epinephrine and norepinephrine) or related compounds (including methyldopa, levodopa, L-tryptophan, L-tyrosine and phenylalanine) while taking phenelzine. Combining them with an MAO inhibitor can cause a hypertensive crisis. (all countries)
Do not eat foods high in tyramine or dopamine while taking phenelzine. Avoid high-protein food that has been aged, fermented, pickled, smoked or allowed to spoil: cheeses (especially aged varieties), pickled herring, beer, wine, liver, yeast extract (including large quantities of brewer’s yeast), dry sausage such as Genoa salami, hard salami, pepperoni and Lebanon bologna, broad (fava) bean pods, and yoghurt. Excessive caffeine and chocolate may also cause a hypertensive reaction. (all countries)
Do not take phenelzine with dextromethorphan (a cough suppressant found in many over-the-counter cough and cold remedies) or with CNS depressants such as alcohol and certain narcotics. (all countries)
Do not take phenelzine with meperidine (pethidine). This combination is contraindicated: excitation, seizures, delirium, very high fever, circulatory collapse, coma and death have been reported after a single dose of meperidine in patients on MAOI therapy. (all countries)
Do not take phenelzine together with, or in rapid succession to, another MAO inhibitor (such as isocarboxazid, tranylcypromine, pargyline, furazolidone or procarbazine). Hypertensive crises, convulsive seizures, fever, marked sweating, excitation, delirium, tremor, coma and circulatory collapse may occur. (all countries)
Do not take phenelzine with serotoninergic medicines such as fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine or dexfenfluramine. This combination is contraindicated and has caused serious reactions including hyperthermia, rigidity, myoclonic movements and death. At least 14 days must pass between stopping an MAO inhibitor and starting a serotonin re-uptake inhibitor, or vice versa, except for fluoxetine, which requires at least 5 weeks before phenelzine is started. (all countries)
Do not take phenelzine with bupropion, or with buspirone. Both combinations are contraindicated, and at least 14 days must elapse between stopping phenelzine and starting either of them. (all countries)
Do not take phenelzine with tryptophan supplements. The combination has caused disorientation, confusion, amnesia, delirium, agitation, hypomanic signs, ataxia, myoclonus, hyperreflexia, shivering, ocular oscillations and Babinski signs. (all countries)
Phenelzine is contraindicated if you are taking guanethidine. (all countries)
Do not undergo elective surgery requiring general anaesthesia while taking phenelzine; it must be stopped at least 10 days beforehand. You should also not be given cocaine, or local anaesthetic containing a sympathomimetic vasoconstrictor. (all countries)

Tell your clinician about

Every other medicine you take, including over-the-counter cough, cold, hay-fever, sinus, appetite-suppressant and herbal products — many contain dextromethorphan or a sympathomimetic and can trigger a hypertensive crisis with phenelzine.
Any planned surgery, dental procedure or emergency care, so that general anaesthesia and sympathomimetic local anaesthetics can be avoided; phenelzine must be stopped at least 10 days before elective surgery.
Any heart, kidney or liver problem, and any history of abnormal liver function tests.
Severe headache, palpitations, neck stiffness or soreness, nausea, vomiting, sweating, or a sudden change in vision while on treatment — these can be the first signs of a hypertensive crisis and need emergency assessment.
Any worsening of depression, agitation, or thoughts of self-harm, particularly in the first weeks of treatment or after a dose change.
Pregnancy, plans for pregnancy, or breastfeeding.

How to take Phenelzine

General Instructions: Take phenelzine exactly as prescribed, usually 1 to 3 times daily. Do not increase your dose or take it more often than directed.. Adult Dosing: Initial dose: 15 mg three times daily. Dosage may be increased by 15 mg every few days as needed. Usual maintenance dose: 60–90 mg per day in divided doses.. Pediatric Dosing: Not recommended for use in children and adolescents due to safety concerns and lack of established efficacy.. Administration: Swallow tablets whole with water. Can be taken with or without food, but take consistently in relation to meals.. When To Seek Review: Do not stop taking phenelzine suddenly without consulting your healthcare provider, as withdrawal symptoms may occur. Tapering is usually required.. Storage: Store at room temperature (20–25°C/68–77°F), away from moisture and heat. Keep out of reach of children.
This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician.

Missed dose

If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. do not take an extra dose to catch up.

Overdose

In case of overdose, seek emergency medical attention or call your local poison control center immediately. Symptoms may include agitation, severe headache, rapid heartbeat, hallucinations, seizures, or loss of consciousness.

Side effects

Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.

Common side effects include dizziness, drowsiness, dry mouth, constipation, weight gain, and sleep disturbances. Some people may also experience blurred vision or swelling of the ankles.

Incidence: Reported in the clinician-authored database; frequency not established

Warning sign

What to notice: Severe headache Stiff neck Rapid or irregular heartbeat Chest pain Sudden confusion or agitation

What to do: Seek immediate medical attention for symptoms such as severe headache, chest pain, shortness of breath, sudden confusion, fever, muscle rigidity, seizures, or signs of hypertensive crisis (very high blood pressure, severe headache, vision changes, vomiting). (1)

Serious warnings

Risk of hypertensive crisis with certain foods and medications — serious

Symptoms: Risk of hypertensive crisis with certain foods and medications. May cause drowsiness or dizziness; use caution with activities requiring alertness. Serotonin syndrome risk if combined with other serotonergic drugs. Not recommended in patients with severe hepatic or renal impairment. Monitor for worsening depression or suicidal thoughts, especially in young adults.

Action: Follow the urgency stated and seek prompt or emergency care when indicated.

Contraindications recorded in the clinician database — serious

Symptoms: Contraindications recorded in the clinician database: Contraindicated in patients with pheochromocytoma, congestive heart failure, severe hepatic or renal impairment, and those taking other MAOIs or serotonergic drugs. Use with caution in patients with epilepsy, diabetes, cardiovascular disease, or a history of suicidal ideation. Strict dietary and medication restrictions are required to prevent hypertensive crisis and serotonin syndrome.

Action: Follow the urgency stated and seek prompt or emergency care when indicated.

Interactions

Medicine or test	Effect	Action
Recorded interactions	Phenelzine interacts with many medications, including other antidepressants, stimulants, certain pain medications, and over-the-counter decongestants. Combining phenelzine with these drugs can lead to serious or life-threatening reactions, such as serotonin syndrome or hypertensive crisis. Always inform your healthcare provider of all medicines and supplements you are taking.	(1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy

Pregnancy category: C. Use only if the potential benefit justifies the potential risk to the fetus.

Breastfeeding

Safety during breastfeeding is not established; use caution.

Children

Frequency: Not applicable.. Weight Based: Not recommended for pediatric use.. Max Daily Dose: Not applicable.. Max Single Dose: Not applicable.. Age Restrictions: Safety not established in children.

Renal_impairment

Renal impairment: Use with caution; no specific dosing adjustments provided. Hepatic impairment: Use with caution; consider lower doses and monitor closely. Elderly: Start at the lower end of the dosing range due to increased sensitivity.

Hepatic_impairment

Monitoring

Storage

The clinician-authored database record does not specify storage conditions for this medicine beyond room temperature. As an oral tablet, standard practice is to store at 20-25 degrees C (68-77 degrees F), away from moisture and heat, out of reach of children; follow the specific product's own label for confirmation.

Study the drug class: SNRIs and other antidepressants

Professional information

Clinician-facing context only. This section does not replace current product labeling.

General

Indication: Major depressive disorder (treatment-resistant/atypical depression)

Dose summary: Initial dose: 15 mg orally three times a day. Maintenance dose: 30 to 90 mg/day in divided doses.

Renal context: Use with caution; no specific dosing adjustments provided. (1)

Mechanism of action

Frequently asked questions

What is phenelzine used for?

Phenelzine is primarily used to treat major depressive disorder, especially when other antidepressants have not been effective. It may also be used off-label for certain anxiety disorders.

How does phenelzine work?

Phenelzine works by inhibiting the enzyme monoamine oxidase, which increases levels of neurotransmitters like serotonin, norepinephrine, and dopamine in the brain. This helps improve mood and reduce symptoms of depression.

What foods should I avoid while taking phenelzine?

Avoid foods high in tyramine, such as aged cheeses, cured meats, fermented foods, soy products, and some alcoholic beverages. These can cause dangerous increases in blood pressure.

What are the signs of a hypertensive crisis?

Signs include severe headache, rapid heartbeat, chest pain, neck stiffness, nausea, vomiting, and vision changes. Seek emergency medical attention if these occur.

Can I take other antidepressants with phenelzine?

No, do not take other antidepressants (SSRIs, SNRIs, tricyclics) with phenelzine or within 14 days of stopping either medication, due to the risk of serious interactions.

How long does it take for phenelzine to work?

It may take several weeks (typically 2–4 weeks) to notice improvement in depressive symptoms. Continue taking the medication as prescribed and consult your doctor if you have concerns.

Is phenelzine safe during pregnancy or breastfeeding?

Phenelzine is generally not recommended during pregnancy or breastfeeding due to potential risks to the baby. Discuss with your healthcare provider for individual assessment.

What happens if I take too much Phenelzine?

Taking too much Phenelzine can lead to a hypertensive crisis, characterized by severe headache, palpitations, and stiff neck, or other serious adverse effects. If you suspect an overdose, seek immediate emergency medical attention. Do not attempt to self-treat or wait for symptoms to worsen, as this can be life-threatening.

Can I drink alcohol while taking Phenelzine?

No, consuming alcohol while taking Phenelzine is strongly discouraged. As a monoamine oxidase inhibitor (MAOI), Phenelzine can interact dangerously with alcohol, potentially leading to a severe hypertensive crisis. This interaction can cause a rapid and dangerous increase in blood pressure, posing significant health risks. Always consult your healthcare provider about alcohol consumption.

Is Phenelzine safe during pregnancy?

The safety of Phenelzine during pregnancy is not well-established, and it is generally categorized as a medication where risks cannot be ruled out. Therefore, it is crucial to consult your doctor immediately if you are pregnant, planning to become pregnant, or breastfeeding. Your healthcare provider can assess the potential risks and benefits to determine the safest course of action for you and your baby.

What is the mechanism of action of Phenelzine?

What is the generic name of Phenelzine?

The generic name is Phenelzine. It is sold under brand names including Nardil, Phenelz, Phenelzine.

What class of drug is Phenelzine?

Phenelzine is classed as: Monoamine Oxidase Inhibitor (MAOI) Antidepressant.

References

Phenelzine - Clinician-authored medicine recordMedGuideGlobal clinician-authored medicine record (internal Supabase medicines table) · International (internal database) · accessed 2026-08-07 · source 1
PHENELZINE SULFATE TABLET, FILM COATED [MYLAN PHARMACEUTICALS INC.] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 2
Phenelzine — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 3
Phenelzine Sulfate — FDA approval record (Drugs@FDA ANDA200181)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 4
Phenelzine — RxNorm normalized drug concept (RXCUI 8123)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 5

Brand names by country

Single-ingredient Phenelzine names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.

Priority countries

United States

Nardil15 mg · parke-davis div of pfizer inc

Canada

NARDIL

View brands in additional countries.