Overview and Classification

Paroxetine is a selective serotonin reuptake inhibitor (SSRI) used to treat various mental health conditions.

Classified under antidepressants, it is commonly prescribed for major depressive disorder, generalized anxiety disorder, panic disorder, and social anxiety disorder.

Mechanism of Action

Paroxetine works by inhibiting the reuptake of serotonin, a neurotransmitter, into the presynaptic neuron.

Increased serotonin levels in the synaptic cleft enhance mood and emotional stability.

Dosage Forms Available

Paroxetine is available in conventional tablets, extended-release tablets, and oral suspension forms.

The dosage strength varies, typically ranging from 10 mg to 40 mg tablets and 12.5 mg to 37.5 mg for extended-release.

Administration Guidelines

Paroxetine should be taken orally, usually once daily in the morning, with or without food.

Extended-release tablets should not be crushed or chewed; they must be swallowed whole.

Initial Dosage

The initial dose for major depressive disorder generally starts at 20 mg per day, which may be adjusted by the healthcare provider.

For panic disorder, the starting dose can be lower, often around 10 mg daily, with gradual increments.

Adjustment and Maintenance

Dosage adjustments are typically made at intervals of at least one week to give the medication time to take effect.

Maintenance doses may vary, but effective long-term treatment often involves 20 mg to 50 mg daily.

Discontinuation Protocol

Abrupt discontinuation should be avoided due to potential withdrawal symptoms; dose tapering is recommended.

Gradual dosage reduction can help mitigate adverse effects such as dizziness, sensory disturbances, or flu-like symptoms.

Special Population Considerations

In elderly patients, lower doses may be necessary due to the increased risk of side effects and altered pharmacokinetics.

Patients with hepatic or renal impairment require dose adjustments to prevent accumulation and toxicity.

Common Side Effects

Frequently reported side effects include nausea, dizziness, drowsiness, dry mouth, and sweating.

Some patients experience sexual dysfunction, including decreased libido, impotence, or difficulty achieving orgasm.

Serious Adverse Reactions

Serious side effects may include serotonin syndrome, characterized by agitation, hallucinations, tachycardia, and hyperthermia.

Other severe reactions can involve severe mood changes, suicidal thoughts, and sudden eye pain or changes in vision.

Drug Interactions

Concurrent use with monoamine oxidase inhibitors (MAOIs), other SSRIs, or serotonergic drugs can increase the risk of serotonin syndrome.

Paroxetine may interact with anticoagulants, antiplatelet agents, and nonsteroidal anti-inflammatory drugs (NSAIDs), increasing bleeding risk.

Contraindications

Paroxetine is contraindicated in patients with hypersensitivity to the drug or its components.

It should not be used in conjunction with thioridazine or pimozide due to potential cardiovascular effects.

Pregnancy and Lactation

Paroxetine is categorized under Pregnancy Category D, indicating potential risk to the fetus.

The drug is excreted in breast milk, necessitating caution and consultation with a healthcare provider for breastfeeding mothers.

Monitoring Parameters

Regular assessment of mental health status is crucial to evaluate treatment effectiveness and adjust dosages as needed.

Monitoring for signs of serotonin syndrome and withdrawal symptoms upon dose changes or discontinuation is recommended.

Storage Conditions

Store paroxetine at room temperature, away from moisture and direct sunlight.

Keep out of reach of children and pets to prevent accidental ingestion.

Patient Education Points

Inform patients about the potential time lag before symptom improvement and the importance of adherence to the prescribed regimen.

Discuss the need to avoid alcohol consumption due to its potential to exacerbate side effects and impair efficacy.