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Resources › Psychotropics A-Z › Paroxetine | Paxil | Paxil
Selective Serotonin Reuptake Inhibitor (SSRI)

Paroxetine | Paxil

Clinical Overview

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) indicated for major depressive disorder, obsessive-compulsive disorder, panic disorder, social anxiety disorder, generalized anxiety disorder, and post-traumatic stress disorder. It is known for its potent serotonin reuptake inhibition and significant anticholinergic properties among SSRIs.

Primary Clinical Applications

Paroxetine is indicated for multiple psychiatric conditions including depression, various anxiety disorders, OCD, and PTSD. It is particularly effective for anxiety disorders but requires careful consideration due to its discontinuation syndrome risk and drug interaction profile.

Mechanism and Clinical Characteristics

Paroxetine selectively inhibits serotonin reuptake with minimal effects on norepinephrine or dopamine. It has the shortest half-life among SSRIs and the most potent CYP2D6 inhibition, leading to significant drug interactions and withdrawal symptoms if discontinued abruptly.

Special Considerations

The medication requires gradual tapering due to high risk of discontinuation syndrome. It has more anticholinergic effects than other SSRIs and significant potential for drug interactions through CYP2D6 inhibition.

Prescribing Information

Dosing & Administration

Major Depressive Disorder:

  • Initial: 20 mg daily in morning
  • Range: 20-50 mg daily
  • Maximum: 50 mg daily

Panic Disorder:

  • Initial: 10 mg daily, increase to 40 mg daily
  • Range: 10-60 mg daily

Social Anxiety Disorder:

  • Initial and target: 20 mg daily
  • Range: 20-60 mg daily

OCD:

  • Initial: 20 mg daily
  • Target: 40 mg daily
  • Maximum: 60 mg daily

Elderly:

  • Initial: 10 mg daily
  • Maximum: 40 mg daily

Indications

  • Major depressive disorder
  • Obsessive-compulsive disorder
  • Panic disorder
  • Social anxiety disorder
  • Generalized anxiety disorder
  • Post-traumatic stress disorder

Contraindications

  • MAOI use within 14 days
  • Thioridazine use
  • Pimozide use
  • Known hypersensitivity to paroxetine

Warnings & Precautions

  • Boxed Warning: Increased suicidal risk in patients under 25 years
  • Discontinuation syndrome: Taper gradually to avoid withdrawal
  • Serotonin syndrome: Risk with concurrent serotonergic drugs
  • Bleeding risk: Increased with anticoagulants
  • Hyponatremia: Monitor electrolytes, especially in elderly

Drug Interactions

  • MAOIs: Contraindicated – risk of serotonin syndrome
  • Thioridazine/Pimozide: Contraindicated – QT prolongation
  • CYP2D6 substrates: Increased levels (codeine, tamoxifen)
  • Warfarin: Increased bleeding risk
  • Phenytoin: Decreased paroxetine levels

Adverse Reactions

Common (≥5%):

  • Nausea, somnolence, insomnia, dizziness, sexual dysfunction

Discontinuation-Related:

  • Dizziness, electric shock sensations, flu-like symptoms

Special Populations

  • Pregnancy: Category D – avoid in pregnancy
  • Elderly: Lower starting dose, monitor for hyponatremia
  • Hepatic impairment: Reduce dose in severe impairment
Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. Always consult with qualified healthcare professionals before making any treatment decisions. Individual patient circumstances may vary significantly.