Paxil 40 mg is a prescription antidepressant with the active ingredient paroxetine, belonging to the SSRI (Selective Serotonin Reuptake Inhibitor) class. It’s used to treat several mood, anxiety, and trauma-related disorders.

Quick Overview

• Brand name: Paxil

• Generic name: Paroxetine

• Strength: 40 mg

• Drug class: SSRI (Selective Serotonin Reuptake Inhibitor)

• Form: Tablet (also available as Paxil CR – controlled-release)

• Prescription required

Used For

• Major Depressive Disorder (MDD)

• Generalized Anxiety Disorder (GAD)

• Social Anxiety Disorder (SAD)

• Obsessive-Compulsive Disorder (OCD)

• Panic Disorder

• Post-Traumatic Stress Disorder (PTSD)

• Premenstrual Dysphoric Disorder (PMDD)

• Hot flashes (off-label)

How It Works

Paroxetine works by increasing serotonin levels in the brain. It does this by blocking serotonin reuptake, allowing more of this “feel-good” neurotransmitter to stay active between nerve cells, which improves mood, sleep, and emotional stability.

How to Take It

• Typical daily dose: 20–50 mg

• 40 mg is a higher-end dose, often used after titration based on symptom severity

• Usually taken once daily, preferably in the morning

• Take with or without food

• May take 2–6 weeks to see full benefits

• Do not stop abruptly—must taper off to prevent withdrawal symptoms

Common Side Effects

• Nausea

• Drowsiness or fatigue

• Dry mouth

• Dizziness

• Sexual side effects (low libido, difficulty reaching orgasm)

• Weight gain

• Sweating

• Constipation or diarrhea

Serious Risks

• Suicidal thoughts (especially in young adults under 25)

• Serotonin syndrome (can occur when combined with other serotonergic meds)

• Withdrawal symptoms: “brain zaps,” irritability, insomnia, flu-like symptoms

• Increased risk of birth defects if used during pregnancy

• Hyponatremia (low sodium levels), especially in older adults

• Mania in people with undiagnosed bipolar disorder

 Drug Interactions

Avoid with:

• MAOIs (dangerous interactions)

• Other SSRIs or SNRIs

• St. John’s Wort

• Triptans, Tramadol, and other serotonergic drugs (risk of serotonin syndrome)

• Blood thinners (can increase bleeding risk)

 Summary

Paxil 40 mg (Paroxetine) is a strong SSRI that’s effective for depression, anxiety, PTSD, and OCD, but it’s also notoriously associated with withdrawal symptoms and weight gain more than some other SSRIs. It’s best for those needing strong symptom control—but requires consistent use and careful tapering if stopping.