Paroxetine
Brand names: Seroxat
Paroxetine is a selective serotonin reuptake inhibitor (SSRI) used for depression and a range of anxiety disorders, including generalised anxiety, panic disorder, social anxiety, obsessive-compulsive disorder and post-traumatic stress disorder.
Adult dose
Dose adjustments
Increased plasma concentrations of paroxetine occur in patients with severe renal impairment (creatinine clearance less than 30 ml/minute); dosage should therefore be restricted to the lower end of the dosage range.
Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.
US labelling (FDA)
Reference — US labelling, may differ from UKRecommended starting and maximum daily dosage for MDD, OCD, PD, and PTSD: ( 2.2 ) Indication Starting Daily Dose Maximum Daily Dose MDD 20 mg 50 mg OCD 20 mg 60 mg PD 10 mg 60 mg PTSD 20 mg 50 mg Recommended starting dosage for SAD and GAD is 20 mg daily. ( 2.3 ) Elderly patients, patients with severe renal impairment or severe hepatic impairment: Starting dosage is 10 mg daily. Maximum dosage is 40 mg daily. ( 2.4 ) When discontinuing paroxetine tablets, reduce dosage gradually. ( 2.6 , 5.7 ) 2.1 Administration Information Administer paroxetine tablets as a single daily dose in the morning, with or without food. 2.2 Recommended Dosage for MDD, OCD, PD, and PTSD The recommended starting …
Source: US FDA prescribing information (openFDA / DailyMed), label dated 2026-04-16. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.
Contraindications
- Hypersensitivity to the active substance(s) or to any of the excipients
- Combination with monoamine oxidase inhibitors (MAOIs) — in exceptional circumstances linezolid (a reversible non-selective MAOI) can be given with paroxetine only where there are facilities for close observation of symptoms of serotonin syndrome and monitoring of blood pressure
- Combination with thioridazine
- Combination with pimozide
Side effects
- Common: somnolence, insomnia, agitation, abnormal dreams (including nightmares)
- Common: dizziness, tremor, headache, impaired concentration; blurred vision
- Common: increases in cholesterol levels, decreased appetite; rare hyponatraemia (predominantly in elderly, sometimes due to SIADH)
- Uncommon: abnormal bleeding predominantly of skin and mucous membranes (including ecchymosis and gynaecological bleeding), leukopenia; uncommon extrapyramidal disorders, confusion, hallucinations
- Uncommon: sinus tachycardia, transient increases or decreases of blood pressure, postural hypotension; very rare serotonin syndrome; frequency not known — suicidal ideation, suicidal behaviour and aggression
Interactions
- Irreversible MAOIs — paroxetine may only be initiated two weeks after discontinuation; at least one week should elapse between stopping paroxetine and starting any MAOI
- Reversible MAOIs (e.g. moclobemide, linezolid, methylthioninium chloride/methylene blue) — paroxetine may only be initiated at least 24 hours after discontinuation
- Thioridazine — contraindicated in combination
- Pimozide — contraindicated in combination
Clinical monograph
How it works
It selectively inhibits the reuptake of serotonin (5-HT) at the presynaptic neuronal membrane, increasing serotonergic neurotransmission. It is among the more potent SSRIs and also has modest anticholinergic activity.
Prescribing in practice
- Paroxetine has a short half-life and no active metabolite, so it is particularly associated with discontinuation symptoms — withdraw by gradual dose tapering rather than stopping abruptly.
- It tends to cause more sedation, anticholinergic effects and weight gain than some other SSRIs, and carries a risk of hyponatraemia and increased gastrointestinal bleeding (greater with concomitant NSAIDs or anticoagulants).
- Generally avoided in pregnancy because of a signal for first-trimester cardiac malformations; consult current prescribing references and the SPC if treatment in pregnancy is being considered.
Monitoring
Monitor mood, anxiety and for emergence of suicidal ideation, especially early in treatment and in younger adults. Watch for hyponatraemia (particularly in older patients) and signs of bleeding. Review for serotonin syndrome if combined with other serotonergic agents.
Counselling the patient
- Do not stop this medicine suddenly — speak to your prescriber so the dose can be reduced gradually to limit withdrawal effects such as dizziness, electric-shock sensations and irritability.
- It may take a few weeks to work, and you may feel more anxious or restless at first — seek advice urgently if you have thoughts of harming yourself.
- Tell your prescriber if you are pregnant or planning pregnancy, and report any unusual bruising or bleeding.
Evidence & guidelines
Guideline-recommended option for depression and anxiety disorders (NICE), though discontinuation symptoms can be more pronounced than with longer-acting SSRIs.
Reference: NICE CG90 (Depression); MHRA SSRIs in Paediatrics Safety Update; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).
Related
Curated clinical cross-links plus same-class fallbacks.
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- Capacity Assessment (Mental Capacity Act) · MCA 2005; Code of Practice
- Acute Psychosis Management · NICE CG178 2014
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