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SSRI (Selective Serotonin Reuptake Inhibitor) Pregnancy: §4.6: some epidemiological studies suggest an increased risk of congenital malformations, particularly cardiovascular, with first-trimester use (risk of a cardiovascular defect less than 2/100 vs about 1/100 in the general population). Paroxetine should only be used during pregnancy when strictly indicated. Abrupt discontinuation should be avoided during pregnancy. Increased risk (less than 2-fold) of postpartum haemorrhage with SSRI/SNRI exposure within the month prior to birth. Neonates should be observed if maternal use continues into later pregnancy (respiratory distress, cyanosis, apnoea, seizures, temperature instability, feeding difficulty, hypoglycaemia, hypertonia/hypotonia, tremor, irritability). Possible increased risk of persistent pulmonary hypertension of the newborn (about 5 cases per 1000 pregnancies vs 1-2 per 1000 in the general population). Breast-feeding: small amounts are excreted into breast milk, infant serum concentrations were undetectable or very low and no drug effects were observed — breast-feeding can be considered.

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.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Major depressive episode: 20 mg daily
Route: Oral
Frequency: Once daily in the morning with food
Max: Major depressive episode, social anxiety disorder/social phobia, generalised anxiety disorder and post-traumatic stress disorder: maximum 50 mg/day. Obsessive compulsive disorder and panic disorder: maximum 60 mg/day. Elderly: the maximum dose should not exceed 40 mg daily.
Source: UK SPC (eMC) for Paroxetine 10 mg Tablets, §4.2 (https://www.medicines.org.uk/emc/product/9582/smpc). MAJOR DEPRESSIVE EPISODE: recommended dose 20 mg daily; improvement generally starts after one week but may only become evident from the second week; dosage should be reviewed and adjusted if necessary within 3 to 4 weeks of initiation and thereafter as judged clinically appropriate; in some patients with insufficient response to 20 mg the dose may be increased gradually up to a maximum of 50 mg a day in 10 mg steps according to response; treat for a sufficient period of at least 6 months to ensure freedom from symptoms. OBSESSIVE COMPULSIVE DISORDER: recommended dose 40 mg daily; start on 20 mg/day and increase gradually in 10 mg increments to the recommended dose; if insufficient response after some weeks, some patients may benefit from gradual increase up to a maximum of 60 mg/day; treatment period may be several months or longer. PANIC DISORDER: recommended dose 40 mg daily; start at 10 mg/day and increase gradually in 10 mg steps according to response (a low initial starting dose is recommended to minimise potential worsening of panic symptomatology early in treatment); maximum 60 mg/day if insufficient response; treatment period may be several months or longer. SOCIAL ANXIETY DISORDER/SOCIAL PHOBIA: recommended dose 20 mg daily; may be increased gradually in 10 mg steps up to a maximum of 50 mg/day; long-term use should be regularly evaluated. GENERALISED ANXIETY DISORDER: recommended dose 20 mg daily; may be increased gradually in 10 mg steps up to a maximum of 50 mg/day. POST-TRAUMATIC STRESS DISORDER: recommended dose 20 mg daily; may be increased gradually in 10 mg steps up to a maximum of 50 mg/day. DISCONTINUATION: abrupt discontinuation should be avoided; the taper regimen used in clinical trials decreased the daily dose by 10 mg at weekly intervals; if intolerable symptoms occur after a dose decrease or on discontinuation, resuming the previously prescribed dose may be considered, then decreasing more gradually. ELDERLY: increased plasma concentrations occur; dosing should commence at the adult starting dose; increasing the dose might be useful in some patients but the maximum should not exceed 40 mg daily. PAEDIATRIC (not expressed as a per-kg dose in the SPC): paroxetine should NOT be used for the treatment of children and adolescents (7-17 years) as controlled clinical trials found it to be associated with increased risk for suicidal behaviour and hostility and efficacy was not adequately demonstrated; use has not been studied in children under 7 years and it should not be used in that age group as safety and efficacy have not been established. Verify any under-18 use against a children's formulary. HEPATIC IMPAIRMENT: increased plasma concentrations occur — dosage should be restricted to the lower end of the dosage range. METHOD OF ADMINISTRATION: once daily in the morning with food; the tablet should not be sucked, chewed or kept in the mouth but swallowed whole immediately with plenty of water (at least 1 glass of 150 ml). §4.5 Interactions was not retrieved in this bundle — the interactions listed below are taken from the §4.3 Contraindications text; verify the full §4.5.

Dose adjustments

Renal

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 UK

Recommended 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.