paroxetine hydrochloride hemihydrate: clinical use

Prescribing considerations

• Review suicide and self-harm risk, particularly in younger adults, during early treatment and after treatment changes.
• Avoid abrupt withdrawal; paroxetine has a comparatively high frequency of discontinuation reactions.
• Use caution with previous mania, epilepsy, bleeding risk, diabetes, angle-closure glaucoma risk, cardiac disease, QT-risk factors and susceptibility to hyponatraemia.
• Systemic exposure may be increased in older people and in severe renal or hepatic impairment.
• Paroxetine is not licensed for treating people under 18 years; trials identified increased suicidal behaviour and hostility without adequately demonstrated efficacy.

Contraindications and cautions

• Hypersensitivity to paroxetine or an excipient
• Concomitant use with a monoamine oxidase inhibitor, except exceptional closely monitored linezolid use described in the SmPC
• Concomitant pimozide or thioridazine
• For the selected lactose-containing product: specified rare hereditary disorders of galactose handling

Monitoring

• Clinical response, tolerability and treatment-emergent suicidality or unusual behavioural change
• Serotonin toxicity when used with serotonergic agents
• Withdrawal symptoms during reduction or after missed tablets
• Bleeding in patients using anticoagulants, antiplatelets or NSAIDs
• Serum sodium where symptoms or risk factors suggest hyponatraemia
• Glycaemic control in diabetes, particularly with pravastatin
• Newborn adaptation if exposure continues into later pregnancy; breastfed infant feeding, behaviour and weight gain where clinically indicated

Clinical pharmacology

Paroxetine is a potent selective inhibitor of neuronal serotonin uptake. It undergoes first-pass metabolism, displays modest non-linear pharmacokinetics, is extensively tissue distributed and protein bound, and is metabolised to largely inactive products. It is also a potent CYP2D6 inhibitor, explaining several clinically important interactions.

Formulation and product differences

• The selected product is a blue, film-coated, capsule-shaped tablet with a score line that permits division into equal halves.
• The selected product contains lactose and is essentially sodium-free.
• Appearance, excipients and score-line suitability can differ between manufacturers; consult the specific product information.

Tablet

Route: Oral

Strengths: 20 mg, 30 mg