phenelzine
Brand names: Nardil
Phenelzine (Nardil) is a medicine used to treat depression. It belongs to a class of drugs called MAO inhibitors.
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.
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.
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.
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.
Storage
Store at room temperature, away from heat, light, and moisture.
Side Effects (from patient reports)
Based on 1,395 FDA adverse event reports.
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
Death-Related Reports
41
Hospitalization Reports
325
Top Indication
Depression
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | DRUG INEFFECTIVE | 330 |
| 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 |
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.
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.
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alprazolam
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amitriptyline
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amphetamine/dextroamphetamine
Adderall, Adderall XR
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aripiprazole
Abilify
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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
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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 1,395 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.
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