Contraindications. MAOI use now or within 14 days of stopping it, linezolid, intravenous methylene blue, liver disease with hepatic impairment, severe kidney impairment (creatinine clearance under 30 mL/min), uncontrolled narrow-angle glaucoma, use with strong CYP1A2 inhibitors (fluvoxamine, ciprofloxacin, enoxacin), hypersensitivity.
Serious adverse effects. Boxed-warning-level risk of suicidal thinking and behaviour in under 25 years. Hepatotoxicity (raised transaminases, rarely hepatitis and liver failure), serotonin syndrome, hyponatraemia, bleeding, hypertension, urinary hesitancy or retention, orthostatic hypotension and falls, mania, seizures, severe discontinuation syndrome.
Common adverse effects. Nausea, dry mouth, constipation, somnolence, dizziness, headache, sweating, reduced appetite, sexual dysfunction.
Interactions. Strong CYP1A2 inhibitors raise levels sharply and are avoided. Paroxetine and fluoxetine (CYP2D6 inhibitors) raise levels. Duloxetine moderately inhibits CYP2D6 and can raise tricyclic antidepressants, flecainide and metoprolol. Serotonin syndrome risk rises with tramadol, triptans and linezolid. Bleeding risk rises with NSAIDs and anticoagulants. Heavy alcohol use adds to liver risk.
Common prescribing errors. Prescribing in chronic heavy alcohol use or liver disease; combining with fluvoxamine or ciprofloxacin; not checking blood pressure; opening the capsule.
Special groups.
- Pregnancy: use only if benefit outweighs risk; late exposure can cause neonatal adaptation symptoms and a small risk of postpartum haemorrhage.
- Breastfeeding: low transfer into milk; acceptable with infant monitoring.
- Children: not advised in under 18 years for depression.
- Older adults: raised risk of hyponatraemia, falls and urinary retention; start 30 mg.
- Kidney impairment: no adjustment for mild to moderate; avoid under 30 mL/min.
- Liver impairment: contraindicated in hepatic impairment.
