Drug Guide
Paroxetine Hydrochloride
Classification
Therapeutic: Antidepressant, Selective Serotonin Reuptake Inhibitor (SSRI)
Pharmacological: Selective Serotonin Reuptake Inhibitor (SSRI)
FDA Approved Indications
- Major depressive disorder
- Obsessive-compulsive disorder (OCD)
- Panic disorder
- Social anxiety disorder
- Post-traumatic stress disorder (PTSD)
- Generalized anxiety disorder (GAD)
- Hot flashes associated with menopause
Mechanism of Action
Paroxetine selectively inhibits the reuptake of serotonin into presynaptic neurons, increasing serotonin levels in the synaptic cleft and enhancing serotonergic neurotransmission.
Dosage and Administration
Adult: Typically 20 mg once daily, with adjustments based on response and tolerability.
Pediatric: Not generally recommended below age 18 except for OCD in children aged 7-17, starting at 10-20 mg/day.
Geriatric: Start at lower doses (e.g., 10 mg daily) due to increased sensitivity.
Renal Impairment: Use with caution; may require dose adjustments.
Hepatic Impairment: Start at lower doses; monitor closely.
Pharmacokinetics
Absorption: Well absorbed orally, with high bioavailability.
Distribution: Widely distributed; protein binding approximately 95%.
Metabolism: Primarily hepatic via CYP2D6 and CYP3A4.
Excretion: Metabolites excreted in urine; small amount excreted unchanged in urine.
Half Life: Approximately 21 hours, allowing once daily dosing.
Contraindications
- Hypersensitivity to paroxetine or excipients.
- Concomitant use with monoamine oxidase inhibitors (MAOIs).
Precautions
- History of mania or bipolar disorder.
- Increased risk of suicidal thoughts in young adults, adolescents, and children.
- Use cautiously in patients with bleeding disorders or on anticoagulants.
- Monitor for serotonin syndrome, especially when combined with other serotonergic drugs.
- Pregnancy category D — risk of congenital malformations. Use only if benefits justify potential risks.
Adverse Reactions - Common
- Nausea (Common)
- Somnolence (Common)
- Headache (Common)
- Insomnia (Common)
- Sweating (Common)
Adverse Reactions - Serious
- Serotonin syndrome (Rare)
- Suicidal ideation (Rare)
- QT prolongation and arrhythmias (Rare)
- Hyponatremia, especially in elderly (Rare)
- Emotional blunting or dizziness (Uncommon)
Drug-Drug Interactions
- MAOIs
- Tricyclic antidepressants
- Other serotonergic drugs (e.g., triptans, lithium, tramadol)
- Warfarin and other anticoagulants
Drug-Food Interactions
- Alcohol, which can increase sedation and impair judgment.
Drug-Herb Interactions
N/ANursing Implications
Assessment: Monitor mood, suicidal ideation, and response to therapy. Check baseline blood pressure and ECG if indicated.
Diagnoses:
- Risk for suicide
- Risk for bleeding
- Imbalanced nutrition related to gastrointestinal discomfort
Implementation: Administer with food to reduce gastrointestinal upset. Advise patients not to discontinue abruptly.
Evaluation: Assess for therapeutic effectiveness and side effects. Adjust dose accordingly.
Patient/Family Teaching
- Take medication exactly as prescribed.
- Do not stop medication suddenly without consulting healthcare provider.
- Report worsening depression, suicidal thoughts, or unusual bleeding.
- Limit alcohol intake.
- Be aware of potential side effects like nausea, dizziness, or sleep disturbances.
Special Considerations
Black Box Warnings:
- Increased risk of suicidal thinking and behavior in children, adolescents, and young adults.
Genetic Factors: Consider CYP2D6 polymorphisms affecting metabolism.
Lab Test Interference: May cause false-positive urine screening for drugs of abuse.
Overdose Management
Signs/Symptoms: Dizziness, tremors, vomiting, tachycardia, seizures, serotonin syndrome.
Treatment: Supportive care, activated charcoal if recent ingestion, benzodiazepines for agitation, serotonin antagonists for serotonin syndrome, and intensive care monitoring as needed.
Storage and Handling
Storage: Store at room temperature, 20-25°C (68-77°F).
Stability: Stable for at least 24 months when stored properly.