Paxil vs. Fluoxetine

See how Paxil and Fluoxetine compare on approved uses, dosing, side effects, and cost.

Key Takeaways

  • Paxil and fluoxetine are both SSRIs used to treat depression, but Paxil also carries specific approvals for generalized anxiety disorder, social anxiety disorder, and PTSD that fluoxetine does not have.

  • Fluoxetine's long-acting active metabolite makes it less likely than Paxil to cause abrupt discontinuation symptoms if a dose is missed.

  • Fluoxetine costs roughly $25 to $60 a month as a generic, while Paxil typically runs $300 to $310 a month, a meaningful difference for many patients.

Paxil vs. Fluoxetine Drug Summary

Paxil

Paxil (paroxetine) is a selective serotonin reuptake inhibitor (SSRI) used to treat major depressive disorder, obsessive-compulsive disorder, panic disorder, social anxiety disorder, generalized anxiety disorder, and PTSD. It comes as an immediate-release tablet taken once daily, with extended-release and liquid forms also available.

Fluoxetine

Fluoxetine is a selective serotonin reuptake inhibitor (SSRI) approved for major depressive disorder, OCD, panic disorder, and bulimia nervosa, plus bipolar depression when combined with olanzapine. It is taken once daily as a capsule, tablet, or liquid, with a once-weekly maintenance option for some patients.

Paxil vs. Fluoxetine Side Effects

Paxil

Most common
nausea (up to 26%)
somnolence (up to 23%)
insomnia (up to 13%)
dry mouth (up to 18%)

Fluoxetine

Most common
nausea (up to 21%)
somnolence (up to 13%)
insomnia (up to 33%)
headache (up to 21%)

Paxil vs. Fluoxetine Dosage

Paxil

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 20 mg once daily At the start
Maximum dose 50 mg once daily If needed
Dose changes 3 increases As tolerated

Fluoxetine

Dosage
Dosage Table
STAGE DOSE WHEN
Starting dose 10 mg once daily Week 1
Maximum dose 90 mg once weekly If needed
Dose changes 4 increases Every week

Paxil vs. Fluoxetine Indications

Paxil

Paxil is FDA-approved for a broad range of psychiatric conditions beyond depression, including several distinct anxiety disorders. It is not approved for use in children or adolescents.

  • Major depressive disorder

  • Obsessive-compulsive disorder

  • Panic disorder

  • Social anxiety disorder

  • Post-traumatic stress disorder

Fluoxetine

Fluoxetine covers major depression and OCD in both adults and children, plus approvals not shared by Paxil, such as bulimia nervosa and bipolar depression combined with olanzapine. It also has several off-label uses, including PMDD and binge eating disorder.

  • Major depressive disorder (adults and children 8-18)

  • OCD (adults and children 7-17)

  • Bulimia nervosa

  • Bipolar I depression (with olanzapine)

  • Panic disorder

Paxil vs. Fluoxetine Pros and Cons

Paxil

Paxil has specific FDA approval for generalized anxiety disorder, social anxiety disorder, and PTSD, making it a common choice when anxiety symptoms dominate. Its short half-life means missed doses can cause discontinuation symptoms more quickly than with fluoxetine.

Pros

  • FDA-approved specifically for GAD, social anxiety, and PTSD

  • Available in extended-release form for steadier dosing

  • Long clinical track record since 1992

Cons

  • Strong CYP2D6 inhibitor increases risk of drug interactions

  • Short half-life often causes more noticeable discontinuation symptoms

  • Not approved for use in children or adolescents

Fluoxetine

Fluoxetine's long-acting metabolite makes missed doses less likely to cause withdrawal symptoms, and its low cost reflects decades of generic availability. It also carries pediatric approvals for depression and OCD that Paxil does not have.

Pros

  • Approved for depression and OCD in children as young as 7-8

  • Long half-life leads to milder discontinuation symptoms

  • Roughly $25 to $60 per month, far less expensive than Paxil

Cons

  • Not approved for GAD, social anxiety disorder, or PTSD

  • More likely to cause activating effects like insomnia than sedation

  • Higher risk of drug interactions when combined with olanzapine

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