Paroxetine

1. Introduction

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) used to treat various mental health conditions, including depression, anxiety disorders, and post-traumatic stress disorder (PTSD). It works by increasing serotonin levels in the brain, which helps improve mood and emotional stability.

2. Indications

  • Major depressive disorder (MDD)
  • Generalised anxiety disorder (GAD)
  • Panic disorder (PD)
  • Social anxiety disorder (SAD)
  • Obsessive-compulsive disorder (OCD)
  • Post-traumatic stress disorder (PTSD)
  • Premenstrual dysphoric disorder (PMDD)
  • Vasomotor symptoms associated with menopause (off-label use)

3. Dosage

Adults:

  • Depression: 20 mg once daily; may increase by 10 mg weekly to a maximum of 50 mg/day.
  • Anxiety Disorders (e.g., GAD, SAD, PTSD, OCD): 10–20 mg once daily; titrate up to 40–60 mg/day if needed.
  • Panic Disorder: Start with 10 mg once daily; titrate up to 40 mg/day (maximum: 60 mg/day).

Elderly or Patients with Renal/Hepatic Impairment:

  • Start with 10 mg once daily; maximum dose: 40 mg/day.

Children:

  • Not recommended for use in children due to insufficient safety and efficacy data.

4. Administration

  • Take orally, preferably in the morning with or without food.
  • Swallow tablets whole with water; do not crush or chew.

5. Forms Available

  • Immediate-release tablets: 10 mg, 20 mg, 30 mg, 40 mg
  • Extended-release tablets: 12.5 mg, 25 mg, 37.5 mg
  • Oral suspension: 10 mg/5 mL

6. Side Effects

6.1 Common Side Effects:

  • Nausea
  • Dry mouth
  • Drowsiness
  • Insomnia
  • Dizziness
  • Sexual dysfunction (e.g., decreased libido, erectile dysfunction)

6.2 Less Common Side Effects:

  • Sweating
  • Weight gain or loss
  • Tremor

6.3 Rare but Serious Side Effects:

  • Serotonin syndrome (confusion, rapid heart rate, agitation)
  • Suicidal ideation (particularly in young adults and adolescents)
  • Hyponatraemia (low sodium levels)
  • Increased risk of bleeding (when combined with NSAIDs or anticoagulants)

7. Warnings

  • Suicidal Ideation: Increased risk of suicidal thoughts and behaviours, particularly in patients under 25 years. Close monitoring is essential during the initial weeks of therapy.
  • Serotonin Syndrome: Avoid combining Paroxetine with other serotonergic drugs (e.g., MAOIs, triptans).
  • Discontinuation Syndrome: Abrupt cessation may cause withdrawal symptoms (e.g., headache, dizziness, irritability); taper gradually.

8. Precautions

  • Use cautiously in patients with a history of seizures, bipolar disorder, or bleeding disorders.
  • Avoid alcohol while taking Paroxetine, as it may worsen side effects like drowsiness or dizziness.
  • Monitor for changes in behaviour, especially in the initial weeks of treatment.

9. Interactions

  • Monoamine oxidase inhibitors (MAOIs): Contraindicated; wait at least 14 days between stopping an MAOI and starting Paroxetine.
  • Anticoagulants/Antiplatelets (e.g., warfarin, aspirin): Increased risk of bleeding.
  • CYP2D6 inhibitors (e.g., fluoxetine, bupropion): May increase Paroxetine levels.
  • NSAIDs: Increased risk of gastrointestinal bleeding.

10. Monitoring Parameters

  • Monitor for symptom improvement (e.g., mood, anxiety, sleep).
  • Assess for side effects, particularly serotonin syndrome and behavioural changes.
  • Periodic monitoring of sodium levels, especially in elderly patients.

11. Use in Children

  • Not recommended due to an increased risk of suicidal ideation and insufficient data on efficacy.

12. Use in Pregnancy

  • Category D: Paroxetine is associated with an increased risk of congenital malformations (e.g., cardiovascular defects) when used in the first trimester. Use only if benefits outweigh risks.

13. Use in Elderly

  • Start at lower doses due to increased sensitivity to side effects like hyponatraemia. Monitor for dizziness, falls, and behavioural changes.

14. Use in Kidney Disease

  • Dose adjustment is recommended in severe renal impairment.

15. Use in Liver Disease

  • Reduce the dose in patients with hepatic impairment due to reduced clearance of Paroxetine.

16. Patient Counselling Points

  • Take Paroxetine at the same time each day, preferably in the morning to reduce the risk of insomnia.
  • Avoid alcohol and other sedatives while on Paroxetine.
  • Do not stop taking the medication suddenly; consult your doctor for a tapering schedule.
  • Report any worsening of mood, unusual behavioural changes, or suicidal thoughts immediately.
  • Common side effects like nausea and drowsiness may improve after a few weeks of treatment.

17. Table of Brand Names, Manufacturer, and Prices in USD

Brand NameManufacturerStrength/Dosage FormPrice (USD)
PaxilGSK20 mg Tablet$80 (30 tablets)
Paxil CRGSK25 mg Extended-Release Tablet$90 (30 tablets)
SeroxatGSK10 mg Tablet$60 (30 tablets)
Generic ParoxetineVarious20 mg Tablet$20 (30 tablets)

18. 15 FAQs (Frequently Asked Questions)

1. What is Paroxetine used for?
Paroxetine is used to treat depression, anxiety disorders, OCD, PTSD, and related conditions.

2. How does Paroxetine work?
It increases serotonin levels in the brain by inhibiting its reuptake, improving mood and reducing anxiety.

3. What is the usual dose of Paroxetine?
The typical starting dose is 20 mg once daily for depression and anxiety, with a maximum dose of 50–60 mg/day depending on the condition.

4. How long does Paroxetine take to work?
It may take 2–4 weeks to notice improvements in symptoms, with full effects taking 6–8 weeks.

5. Can Paroxetine cause weight gain?
Yes, weight gain is a possible side effect, especially with long-term use.

6. Is Paroxetine addictive?
No, Paroxetine is not addictive, but sudden discontinuation may cause withdrawal symptoms.

7. Can Paroxetine be used during pregnancy?
Paroxetine is not recommended during pregnancy due to an increased risk of congenital malformations.

8. Can Paroxetine cause drowsiness?
Yes, drowsiness is a common side effect. Avoid driving or operating machinery if affected.

9. Can I drink alcohol while taking Paroxetine?
Alcohol should be avoided as it can worsen drowsiness and dizziness.

10. How should I stop taking Paroxetine?
Do not stop suddenly; consult your doctor to taper the dose gradually to avoid withdrawal symptoms.

11. Can Paroxetine cause sexual dysfunction?
Yes, it is a common side effect, including reduced libido and difficulty achieving orgasm.

12. Does Paroxetine interact with other medications?
Yes, it interacts with MAOIs, anticoagulants, NSAIDs, and serotonergic drugs.

13. What should I do if I miss a dose?
Take the missed dose as soon as possible, but skip it if it’s close to the next dose. Do not double the dose.

14. Can Paroxetine cause suicidal thoughts?
Yes, it may increase suicidal thoughts, especially in patients under 25 years. Close monitoring is essential.

15. Is Paroxetine safe for long-term use?
Yes, but regular monitoring by a doctor is recommended to manage potential side effects.