Prescription medication · Monoamine Oxidase Inhibitor (MAOI)
phenelzine
Also sold as Nardil. This medicine treats depression, especially when it involves anxiety, phobias, or hypochondria.
Data updated 2026-05-15
- 1,551
- FDA reportsRarely reported
- 27
- InteractionsSeveral interactions
- 78% less
- Generic vs brandBig savings
- $2.44
- Brand price (NADAC)
What the data shows
phenelzine (Nardil) is a prescription Monoamine Oxidase Inhibitor (MAOI), among the least-reported drugs the FDA tracks (1,551 FDA reports), whose generic runs roughly half the brand price or less (78% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
phenelzine (Nardil) is a prescription Monoamine Oxidase Inhibitor (MAOI). This medicine treats depression, especially when it involves anxiety, phobias, or hypochondria.
Phenelzine (Nardil) is a medicine used to treat depression. It belongs to a class of drugs called MAO inhibitors.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$2.44/unit
Generic Price
$0.53/unit
Generic Savings
78%
Generic Available
Yes (1 manufacturer)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine treats depression, especially when it involves anxiety, phobias, or hypochondria.
Common side effects
Dizziness, Headache, Drowsiness
Key warnings
Antidepressants may increase the risk of suicidal thoughts and behavior in children, teens, and young adults.
The sections below are summarized in plain English from phenelzine's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Phenelzine works by blocking an enzyme called monoamine oxidase (MAO) in your body. MAO breaks down certain chemicals in the brain, like serotonin and norepinephrine. By blocking MAO, phenelzine helps increase the levels of these chemicals, which can improve mood.
How to Take It
The usual starting dose is one 15 mg tablet three times a day. Your doctor may increase the dose to at least 60 mg per day, as you can tolerate it. Some people may need up to 90 mg per day. It may take at least 4 weeks at 60 mg to see if it's working.
This is a plain-language summary of phenelzine's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
It is not known if phenelzine can harm an unborn baby. Talk to your doctor if you are pregnant, planning to become pregnant, or breastfeeding.
This is a plain-language summary of phenelzine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
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 continue with your regular schedule.
This is a plain-language summary of phenelzine's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature, away from heat, light, and moisture.
Side Effects (from patient reports)
Based on 1,551 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for phenelzine, by number of reports
- Feeling sad or hopeless
Feeling sad or hopeless
187 reports
- Head pain
Head pain
136 reports
- Feeling worried or nervous
Feeling worried or nervous
129 reports
- Gaining weight
Gaining weight
120 reports
- Trouble sleeping
Trouble sleeping
104 reports
- Feeling lightheaded or unsteady
Feeling lightheaded or unsteady
99 reports
- The medicine is reacting with another medicine
The medicine is reacting with another medicine
99 reports
- Problem with the medicine
Problem with the medicine
97 reports
- Feeling tired
Feeling tired
94 reports
- Feeling strange
Feeling strange
89 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for phenelzine each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where phenelzine sits
phenelzine has more FDA adverse-event reports than 10% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is phenelzine; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 1,551 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
1,551
Reports Mentioning Death
41
2.6% of reports — not proof of cause
Hospitalization Reports
325
Top Indication
Depression
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 2 | DEPRESSION | 187 |
| 3 | HEADACHE | 136 |
| 4 | ANXIETY | 129 |
| 5 | WEIGHT INCREASED | 120 |
| 6 | INSOMNIA | 104 |
| 7 | DIZZINESS | 99 |
| 8 | DRUG INTERACTION | 99 |
| 9 | PHARMACEUTICAL PRODUCT COMPLAINT | 97 |
| 10 | FATIGUE | 94 |
| 11 | FEELING ABNORMAL | 89 |
| 12 | MALAISE | 78 |
| 13 | NAUSEA | 77 |
| 14 | HYPERTENSION | 76 |
| 15 | FALL | 61 |
| 16 | SOMNOLENCE | 57 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
Antidepressants may increase the risk of suicidal thoughts and behavior in children, teens, and young adults. Your doctor will monitor you closely for worsening depression, suicidal thoughts, or unusual changes in behavior. Families and caregivers should also watch for these changes and report them to the doctor. This medicine is not approved for use in children.
Known Drug Interactions
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Mechanism: Both of these drugs increase a chemical in your brain called serotonin. Taking them together can cause dangerously high levels of serotonin, which can be life-threatening.
What to do: Do not take these two medications together. You must wait a specific amount of time when switching between them to avoid a serious reaction.
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Mechanism: These drugs both raise serotonin levels in the brain. Combining them can lead to a dangerous and potentially fatal reaction.
What to do: Avoid using these medications at the same time. Talk to your doctor about how to safely switch from one to the other.
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Mechanism: Combining these drugs can cause too much serotonin to build up in your system. This can lead to very serious side effects that may be fatal.
What to do: This combination should be avoided. Your healthcare provider will need to manage the timing of these medications carefully.
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Mechanism: Both medications increase serotonin levels, and using them together can cause a severe reaction. This happens because the body cannot process the excess serotonin safely.
What to do: Do not use these drugs together. Ensure there is a proper waiting period if you are stopping one and starting the other.
Drug Interactions In patients receiving nonselective monoamine oxidase (MAO) inhibitors in combination with serotoninergic agents (e.g., dexfenfluramine, fluoxetine, fluvoxamine, paroxetine, sertraline, citalopram, venlafaxine) there have been reports of serious, sometimes fatal, reactions.
Mechanism: Both drugs increase the amount of serotonin in your brain, which can cause a very dangerous and life-threatening reaction.
What to do: Do not use these medicines together because the combination can be fatal.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
Can I drink alcohol while taking phenelzine?
What foods should I avoid?
Can I take other medications with phenelzine?
How long does it take for phenelzine to work?
What should I do if I experience side effects?
Can I stop taking phenelzine suddenly?
Will this medicine affect my ability to drive or operate machinery?
What if I need surgery?
How will I know if the medicine is working?
What should I do if I think I have overdosed?
What are the common side effects of phenelzine?
Does phenelzine interact with other medications?
What drug class is phenelzine?
Is there a generic version of phenelzine?
Is phenelzine safe during pregnancy?
Related Medications in Monoamine Oxidase Inhibitor (MAOI)
Other drugs grouped near phenelzine - same-class peers and common alternatives.
acamprosate
Campral
Acamprosate is a medicine that can help you stay away from alcohol if you are alcohol-dependent and have already stopped drinking.
Compare with phenelzine →
alprazolam
Xanax
Alprazolam (Xanax) is a medication that can help you with anxiety and panic disorders.
Compare with phenelzine →
amitriptyline
Elavil
Amitriptyline is a medicine used to treat depression.
Compare with phenelzine →
amphetamine/dextroamphetamine
Adderall, Adderall XR
Adderall XR is a stimulant medicine.
Compare with phenelzine →
aripiprazole
Abilify
Aripiprazole (Abilify) is a medicine used to treat certain mental disorders and mood problems.
Compare with phenelzine →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
Save on phenelzine
Compare prices and find discounts at pharmacies near you. Free coupons can save up to 80% on prescriptions.
Disclosure: This link may earn us a commission at no extra cost to you. See our terms.
What the FDA Data Shows for phenelzine
The FDA label for phenelzine (sold under brand names such as Nardil) classifies it as a prescription-only medication in the Monoamine Oxidase Inhibitor (MAOI) class. This medicine treats depression, especially when it involves anxiety, phobias, or hypochondria. Official labeling lists 15 commonly reported side effects, including Dizziness, Headache, Drowsiness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 1,551 voluntary reports. The database also lists 27 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated moderate severity. NADAC pricing from CMS shows a generic unit cost of $0.53 versus $2.44 for the brand - a 78% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: September 29, 2017
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages