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fluoxetine vs venlafaxine

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

minor Known Drug Interaction

These findings have been confirmed in a clinical drug interaction study comparing the effect of venlafaxine to that of fluoxetine on the CYP2D6-mediated metabolism of dextromethorphan to dextrorphan.

Recommendation: Your doctor may need to monitor you more closely or adjust the doses of other medicines you are taking.

Drug Class
fluoxetine Selective Serotonin Reuptake Inhibitor (SSRI)
venlafaxine Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)
Type
fluoxetine Prescription
venlafaxine Prescription
Summary
fluoxetine

Fluoxetine is a medicine that can help treat depression and other mental health conditions. It belongs to a class of drugs called selective serotonin reuptake inhibitors (SSRIs).

venlafaxine

Venlafaxine is a medication used to treat depression. It helps to improve your mood by affecting certain chemicals in the brain.

What It Treats
fluoxetine

Fluoxetine can treat major depressive disorder in adults and children. It also treats obsessive-compulsive disorder (OCD) in adults and children. Fluoxetine can help with bulimia nervosa (an eating disorder) and panic disorder. Sometimes, it is used with another medicine called olanzapine to treat depression related to bipolar disorder.

venlafaxine

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.

How It Works
fluoxetine

Fluoxetine works by increasing the amount of serotonin in your brain. Serotonin is a chemical that helps regulate mood. By increasing serotonin, fluoxetine can help improve mood and reduce symptoms of depression, OCD, and other conditions.

venlafaxine

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.

Common Side Effects
fluoxetine
  • Abnormal dreams
  • Problems ejaculating
  • Loss of appetite
  • Feeling anxious
  • Feeling weak
venlafaxine
  • Feeling weak or tired
  • Sweating a lot
  • Feeling sick to your stomach
  • Constipation
  • Loss of appetite
FAERS Reports
fluoxetine
  • The medicine is interacting with another medicine 3,336
  • Harmful effect from different substances 3,316
  • Feeling sick to your stomach 3,233
  • Feeling tired 3,155
  • Death by suicide 2,904
venlafaxine
  • 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
Serious Warnings
fluoxetine

Antidepressants may increase the risk of suicidal thoughts and behaviors in children, teenagers, and young adults. Watch closely for worsening depression or suicidal thoughts. Tell your doctor right away if you notice any changes in mood or behavior. Fluoxetine is not approved for use in children younger than 7 years old.

venlafaxine

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.

Pregnancy
fluoxetine

Talk to your doctor if you are pregnant or plan to become pregnant. Fluoxetine should only be used during pregnancy if the benefit outweighs the risk to the baby. Breastfeeding is not recommended while taking fluoxetine.

venlafaxine

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.

Also Compare, Nearby Drugs

How to Read This fluoxetine vs venlafaxine Comparison

fluoxetine is classified in the Selective Serotonin Reuptake Inhibitor (SSRI) 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, fluoxetine has 15,944 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 minor interaction flagged in FDA labeling, attributed to these drugs can affect a liver protein that helps the body process many types of medicine. this can lead to changes in how other drugs you take are broken down.. 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 fluoxetine 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.