Paroxetine is a selective serotonin reuptake inhibitor (SSRI) widely prescribed for the management of major depressive disorder, various anxiety disorders, and related conditions. As a potent and well-studied antidepressant, it works by increasing serotonin levels in the brain, which helps improve mood, reduce anxiety, and restore emotional balance. Its efficacy, tolerability, and established safety profile make it a first-line treatment option in clinical psychiatry and primary care settings worldwide.

Features

• Active ingredient: Paroxetine hydrochloride
• Available in immediate-release and controlled-release tablet formulations
• Standard strengths: 10mg, 20mg, 30mg, 40mg tablets; 12.5mg, 25mg, 37.5mg controlled-release
• FDA-approved for multiple indications including MDD, OCD, panic disorder, social anxiety disorder, GAD, and PTSD
• Bioavailability of approximately 50% after oral administration
• Half-life of approximately 21 hours (immediate-release)
• Extensive metabolism via cytochrome P450 2D6 pathway
• Pregnancy Category D (based on human data showing potential risk)

Benefits

• Significant improvement in depressive symptoms within 2-4 weeks of initiation
• Effective reduction of anxiety and panic attack frequency and severity
• Improvement in overall quality of life and social functioning
• Decreased obsessive-compulsive behaviors and intrusive thoughts
• Long-term maintenance of therapeutic benefits with continued use
• Flexible dosing options to accommodate individual patient needs

Common use

Paroxetine is primarily indicated for the treatment of major depressive disorder (MDD) in adults, characterized by persistent low mood, loss of interest or pleasure, changes in appetite or sleep, fatigue, and difficulty concentrating. It is also FDA-approved for obsessive-compulsive disorder (OCD), where it helps reduce intrusive thoughts and compulsive behaviors. The medication is effective in managing panic disorder with or without agoraphobia, significantly decreasing the frequency and intensity of panic attacks. Additionally, paroxetine is prescribed for social anxiety disorder (social phobia), generalized anxiety disorder (GAD), and post-traumatic stress disorder (PTSD). Off-label uses include premenstrual dysphoric disorder (PMDD), vasomotor symptoms of menopause, and certain chronic pain conditions, though these applications require careful medical supervision.

Dosage and direction

The initial recommended dosage for depression in adults is 20mg once daily, typically taken in the morning with or without food. For elderly patients or those with hepatic impairment, a starting dose of 10mg daily is recommended. Dosage may be gradually increased in 10mg increments at weekly intervals, based on therapeutic response and tolerability, with a maximum recommended dose of 50mg daily for depression. For anxiety disorders, starting doses are often lower (10mg daily) with gradual titration to minimize initial side effects. Controlled-release formulations should be swallowed whole and not crushed or chewed. Consistent daily administration at approximately the same time each day is recommended to maintain steady blood levels. Dosage adjustments should always be made under medical supervision, and treatment should not be abruptly discontinued due to risk of withdrawal symptoms.

Precautions

Patients should be monitored closely for clinical worsening, suicide risk, or unusual changes in behavior, particularly during the initial months of therapy and during dosage adjustments. Paroxetine may impair judgment, thinking, or motor skills; patients should exercise caution when operating machinery or driving until they know how the medication affects them. Alcohol consumption should be avoided as it may increase impairment and potentially worsen depression. Use with caution in patients with history of seizures, as SSRIs may lower seizure threshold. Regular monitoring of blood pressure is recommended, especially in hypertensive patients. Patients with narrow-angle glaucoma should use paroxetine cautiously due to potential pupillary dilation. Those with diabetes should monitor blood glucose levels closely as paroxetine may affect glycemic control. Bone density monitoring may be considered in long-term users due to potential association with increased fracture risk.

Contraindications

Paroxetine is contraindicated in patients taking monoamine oxidase inhibitors (MAOIs) or within 14 days of discontinuing MAOI therapy due to risk of serotonin syndrome. Concurrent use with pimozide or thioridazine is contraindicated due to potential for serious cardiac arrhythmias. It should not be used in patients with known hypersensitivity to paroxetine or any component of the formulation. Use is contraindicated in patients taking linezolid or intravenous methylene blue due to serotonin syndrome risk. Patients with uncontrolled narrow-angle glaucoma should avoid paroxetine. The medication is contraindicated in combination with other serotonergic drugs that significantly increase serotonin activity. Patients with severe hepatic impairment should not use paroxetine without careful consideration and dosage adjustment.

Possible side effect

Common side effects (≥1/10 patients) include nausea, somnolence, headache, dry mouth, and increased sweating. Less frequent side effects (≥1/100 to <1/10) may include asthenia, insomnia, dizziness, tremor, nervousness, anxiety, constipation, diarrhea, decreased appetite, and sexual dysfunction including decreased libido, erectile dysfunction, and anorgasmia. Weight changes (both gain and loss) may occur during treatment. Uncommon but serious side effects (<1/1000) include serotonin syndrome, hyponatremia (especially in elderly patients), abnormal bleeding, angle-closure glaucoma, and discontinuation symptoms upon abrupt withdrawal. Some patients may experience akathisia (restlessness) or extrapyramidal symptoms. Cases of QT interval prolongation have been reported, particularly at higher doses or in susceptible patients.

Drug interaction

Paroxetine is a potent inhibitor of CYP2D6 and may significantly increase plasma concentrations of drugs metabolized by this enzyme, including tricyclic antidepressants, antipsychotics, beta-blockers, and certain antiarrhythmics. Concomitant use with other serotonergic drugs (tramadol, fentanyl, lithium, triptans, St. John’s Wort) increases risk of serotonin syndrome. NSAIDs, aspirin, or other anticoagulants may increase bleeding risk when combined with paroxetine. Drugs that prolong QT interval should be used cautiously. Paroxetine may decrease the effectiveness of tamoxifen through CYP2D6 inhibition. Cimetidine may increase paroxetine concentrations. Phenobarbital and phenytoin may decrease paroxetine levels. The medication may interact with digoxin, increasing its serum concentration.

Missed dose

If a dose is missed, it should be taken as soon as remembered unless it is close to the time for the next scheduled dose. In that case, the missed dose should be skipped and the regular dosing schedule resumed. Patients should not take a double dose to make up for a missed one. Consistency in dosing is important for maintaining therapeutic blood levels, so establishing a routine (such as using a pill organizer or setting daily reminders) can help prevent missed doses. If multiple doses are missed, patients should contact their healthcare provider for guidance, as dosage adjustment or gradual retitration may be necessary to minimize discontinuation symptoms.

Overdose

Paroxetine overdose may manifest as nausea, vomiting, drowsiness, sinus tachycardia, dilated pupils, and dizziness. More severe cases may involve hypertension or hypotension, involuntary muscle contractions, agitation, confusion, and serotonin syndrome. In massive overdoses, seizures, coma, or ECG changes including QT prolongation may occur. There is no specific antidote for paroxetine overdose. Management involves supportive care and symptomatic treatment. Gastric lavage may be considered if presentation is early after ingestion. Activated charcoal may be administered if the patient presents within one hour of ingestion. Maintenance of airway, oxygenation, and ventilation is essential. ECG monitoring is recommended for at least 24 hours. Benzodiazepines may be used for agitation or seizures. Serotonin syndrome should be managed with supportive care and may require cyproheptadine in severe cases.

Storage

Store paroxetine tablets at room temperature (15-30°C or 59-86°F) in their original container, tightly closed, and protected from light and moisture. Keep away from excessive heat and humidity (avoid storage in bathrooms or near kitchen sinks). Controlled-release tablets should be protected from high humidity. Keep all medications out of reach of children and pets. Do not use paroxetine beyond the expiration date printed on the packaging. Properly dispose of any unused or expired medication through medication take-back programs or according to FDA-recommended disposal methods (do not flush unless specifically instructed).

Disclaimer

This information is provided for educational purposes only and does not constitute medical advice. Paroxetine is a prescription medication that should be used only under the supervision of a qualified healthcare professional. Individual response to medication may vary, and the benefits and risks should be carefully discussed with a prescribing physician. This information is not exhaustive and does not cover all possible uses, directions, precautions, or interactions. Patients should always consult their healthcare provider for personalized medical advice and report any side effects or concerns promptly. Never adjust dosage or discontinue medication without medical supervision.

Reviews

Clinical studies and meta-analyses consistently demonstrate paroxetine’s efficacy in treating depression and anxiety disorders. In randomized controlled trials, paroxetine has shown significant superiority over placebo in reducing Hamilton Depression Rating Scale scores, with response rates typically between 50-70% for major depression. Long-term studies support its effectiveness in maintaining remission and preventing relapse. Patient-reported outcomes often indicate improved quality of life, social functioning, and work productivity. However, some reviews note higher rates of certain side effects (particularly sexual dysfunction and weight gain) compared to other SSRIs. Real-world evidence from post-marketing surveillance continues to support its favorable benefit-risk profile when used appropriately in indicated populations under proper medical supervision.