PlainMeds provides educational information only. This is not medical advice. Always consult your doctor or pharmacist.

paroxetine vs phenelzine

Side-by-side comparison of paroxetine and phenelzine. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

moderate Known Drug Interaction

Examples selegiline, tranylcypromine, isocarboxazid, phenelzine, linezolid, methylene blue Pimozide and Thioridazine Clinical Impact Increased plasma concentrations of pimozide and thioridazine, drugs with a narrow therapeutic index, may increase the risk of QTc prolongation and ventricular arrhythmias.

Recommendation: Avoid this combination entirely as it can be very dangerous.

Drug Class
paroxetine Selective Serotonin Reuptake Inhibitor (SSRI)
phenelzine Monoamine Oxidase Inhibitor (MAOI)
Type
paroxetine Prescription
phenelzine Prescription
Summary
paroxetine

Paroxetine (Paxil) is a medicine that can help treat depression and anxiety disorders. It belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs).

phenelzine

Phenelzine (Nardil) is a medicine used to treat depression. It belongs to a class of drugs called MAO inhibitors.

What It Treats
paroxetine

Paroxetine is used to treat several conditions in adults. These include major depressive disorder (MDD), obsessive compulsive disorder (OCD), panic disorder (PD), social anxiety disorder (SAD), generalized anxiety disorder (GAD), and posttraumatic stress disorder (PTSD). It helps to improve mood and reduce anxiety and panic feelings.

phenelzine

This medicine treats depression, especially when it involves anxiety, phobias, or hypochondria. It is often used when other antidepressants haven't worked. It may not be as effective for severe depression with 'endogenous' features.

How It Works
paroxetine

Paroxetine works by increasing the amount of serotonin in your brain. Serotonin is a natural substance that helps regulate mood. By increasing serotonin levels, paroxetine can help improve symptoms of depression and anxiety.

phenelzine

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.

Common Side Effects
paroxetine
  • Abnormal ejaculation
  • Weakness or fatigue
  • Constipation
  • Decreased appetite
  • Diarrhea
phenelzine
  • Dizziness
  • Headache
  • Drowsiness
  • Trouble sleeping
  • Tiredness
FAERS Reports
paroxetine
  • Reaction with another medicine 1,825
  • Tiredness 1,821
  • Feeling sick to your stomach 1,738
  • Harmful effect from different substances 1,579
  • Worry or nervousness 1,476
phenelzine
  • Feeling sad or hopeless 187
  • Head pain 136
  • Feeling worried or nervous 129
  • Gaining weight 120
  • Trouble sleeping 104
Serious Warnings
paroxetine

Antidepressants may increase the risk of suicidal thoughts and behaviors in young adults. Your doctor will monitor you closely for worsening depression or suicidal thoughts. Paroxetine is not approved for use in children.

phenelzine

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.

Pregnancy
paroxetine

Paroxetine may cause harm to your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. Taking paroxetine later in pregnancy may cause problems for the newborn.

phenelzine

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.

Also Compare, Nearby Drugs

How to Read This paroxetine vs phenelzine Comparison

paroxetine is classified in the Selective Serotonin Reuptake Inhibitor (SSRI) drug class, while phenelzine sits within the Monoamine Oxidase Inhibitor (MAOI) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. Both drugs are prescription-only, so a licensed provider must authorize use.

Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, paroxetine has 8,439 submissions while phenelzine has 676. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known moderate interaction flagged in FDA labeling, attributed to taking these two drugs together can cause a dangerous buildup of brain chemicals that may lead to a severe reaction.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between paroxetine and phenelzine - always consult your physician or pharmacist first.

Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.