phenelzine vs venlafaxine
Side-by-side comparison of phenelzine and venlafaxine. 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
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.
Recommendation: Do not use these drugs together. Ensure there is a proper waiting period if you are stopping one and starting the other.
Nardil
Effexor, Effexor XR
Phenelzine (Nardil) is a medicine used to treat depression. It belongs to a class of drugs called MAO inhibitors.
Venlafaxine is a medication used to treat depression. It helps to improve your mood by affecting certain chemicals in the brain.
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.
Venlafaxine is used to treat major depressive disorder. This condition can cause a persistent feeling of sadness or loss of interest in daily activities. It may also help maintain improvement in patients with recurrent depression.
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.
Venlafaxine is a serotonin-norepinephrine reuptake inhibitor (SNRI). It works by increasing the levels of serotonin and norepinephrine in the brain. These chemicals help regulate mood and can be low in people with depression.
- • Dizziness
- • Headache
- • Drowsiness
- • Trouble sleeping
- • Tiredness
- • Feeling weak or tired
- • Sweating a lot
- • Feeling sick to your stomach
- • Constipation
- • Loss of appetite
- Feeling sad or hopeless 187
- Head pain 136
- Feeling worried or nervous 129
- Gaining weight 120
- Trouble sleeping 104
- Feeling sick to your stomach 4,298
- Harmful effects from different substances 4,264
- Feeling tired 4,199
- Head pain 3,740
- Death by suicide 3,170
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.
Antidepressants may increase the risk of suicidal thoughts and behaviors in children, adolescents, and young adults. Your doctor will monitor you closely for worsening depression, suicidal thoughts, or unusual changes in behavior. Venlafaxine is not approved for use in children.
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.
If you are pregnant or breastfeeding, talk to your doctor before taking venlafaxine. Newborns exposed to SNRIs like venlafaxine in the third trimester may have complications requiring hospitalization. Your doctor will carefully consider the risks and benefits of treatment during pregnancy.
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How to Read This phenelzine vs venlafaxine Comparison
phenelzine is classified in the Monoamine Oxidase Inhibitor (MAOI) drug class, while venlafaxine sits within the Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) 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, phenelzine has 676 submissions while venlafaxine has 19,671. 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 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.. 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 phenelzine and venlafaxine - 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.