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Drugs, Supplies and Delivery
Paroxetine
Paroxetine is a selective serotonin reuptake inhibitor (SSRI) widely prescribed for depression, anxiety disorders, and other psychiatric conditions. Known for its potent serotonin reuptake inhibition and mild anticholinergic effects, paroxetine is effective but requires careful management due to its side effect profile and withdrawal potential. This article synthesizes information from the British National Formulary (BNF), Lippincott Textbook of Pharmacology, and Lange Basic & Clinical Pharmacology to provide a detailed overview of paroxetine, including its mechanism, uses, dosing, side effects, precautions, drug interactions, and availability.
Paroxetine selectively inhibits the reuptake of serotonin (5-HT) at the presynaptic neuronal membrane, increasing serotonin availability in the synaptic cleft. This enhances serotonergic neurotransmission, which is associated with improved mood and emotional regulation (Lippincott Textbook of Pharmacology). Paroxetine also has mild anticholinergic properties, which contribute to its side effect profile (Lange Basic & Clinical Pharmacology).
- Major Depressive Disorder (MDD):
- First-line treatment for acute episodes and maintenance therapy to prevent relapse (BNF).
- Generalized Anxiety Disorder (GAD):
- Approved for managing chronic anxiety symptoms.
- Panic Disorder:
- Reduces the frequency and severity of panic attacks.
- Social Anxiety Disorder (SAD):
- Improves symptoms of social phobia.
- Obsessive-Compulsive Disorder (OCD):
- Reduces intrusive thoughts and compulsive behaviors (Lange Basic & Clinical Pharmacology).
- Adults:
- Initial Dose: 10–20 mg once daily, preferably in the morning.
- Maintenance Dose: 20–50 mg daily; maximum 50 mg/day (BNF).
- Elderly or Hepatically Impaired Patients:
- Lower Initial Dose: 10 mg/day, adjusted based on response (Lippincott).
- Children (≥7 years):
- OCD: 10 mg/day, increased to 20–50 mg/day as needed (Lange Basic & Clinical Pharmacology).
Administration:
- Can be taken with or without food.
- Avoid abrupt discontinuation; taper gradually over weeks to prevent withdrawal symptoms (BNF).
- Common: Nausea, dry mouth, somnolence, sweating, and sexual dysfunction (BNF).
- Serious:
- Serotonin Syndrome: Agitation, hyperthermia, and autonomic instability (rare but life-threatening).
- QT Prolongation: Risk of arrhythmias, particularly at high doses.
- Hyponatremia: Especially in elderly patients (Lippincott).
- Suicidal Ideation: Increased risk in adolescents and young adults (Lange Basic & Clinical Pharmacology).
- Contraindications:
- Concurrent use of MAO inhibitors (risk of serotonin syndrome).
- Known hypersensitivity to paroxetine or other SSRIs (BNF).
- Monitoring:
- Monitor for suicidal thoughts, especially during the initial weeks of treatment.
- Serum sodium levels in elderly patients (Lippincott).
- Pregnancy/Lactation:
- Use with caution; potential neonatal withdrawal or persistent pulmonary hypertension (PPHN) (Lange Basic & Clinical Pharmacology).
- MAO Inhibitors: Risk of serotonin syndrome; allow a 2-week washout period after stopping paroxetine (BNF).
- QT-Prolonging Drugs (e.g., amiodarone, antipsychotics): Synergistic risk of arrhythmias.
- CYP2D6 Inhibitors (e.g., fluoxetine): Increase paroxetine levels; monitor for toxicity.
- NSAIDs/Anticoagulants: Elevated bleeding risk due to SSRI-induced platelet dysfunction (Lippincott).
Paroxetine is the generic name. It is marketed under the brand name Paxil® in some regions. Generic formulations are widely available as:
- Tablets: 10 mg, 20 mg, 30 mg, 40 mg.
- Controlled-Release Tablets: 12.5 mg, 25 mg, 37.5 mg.
- Oral Suspension: 10 mg/5 mL (BNF).
