paroxetine hydrochloride anhydrous: clinical use

Prescribing considerations

• Assess suicide and self-harm risk before treatment and monitor clinical worsening, particularly during early treatment and after prescription changes.
• Discuss withdrawal before initiation. Avoid abrupt cessation because paroxetine has a comparatively high frequency of withdrawal reactions.
• Review bleeding risk, serotonergic medicines and CYP2D6-mediated interactions, particularly tamoxifen.
• Use caution with previous mania, epilepsy, diabetes, glaucoma, cardiac disease, QT-risk factors, hepatic impairment or severe renal impairment.
• The selected product is not indicated for patients younger than 18 years.

Contraindications and cautions

• Hypersensitivity to paroxetine or an excipient
• Concurrent monoamine oxidase inhibitor treatment or use without the required switching interval
• Concurrent thioridazine
• Concurrent pimozide

Monitoring

• Mood, suicidality, agitation, akathisia and manic symptoms
• Withdrawal symptoms during planned discontinuation
• Serum sodium when clinically indicated, especially in older people or those with additional risk factors
• Bleeding, glycaemic control and seizure occurrence where relevant
• ECG and electrolytes when cardiac or QT-prolongation risk warrants assessment
• Newborn adaptation when exposure continues into late pregnancy

Clinical pharmacology

Paroxetine is a potent, selective serotonin-reuptake inhibitor and a strong CYP2D6 inhibitor. Oral absorption is followed by first-pass metabolism, pharmacokinetics are mildly non-linear, tissue distribution and protein binding are extensive, and the elimination half-life is generally about one day.

Formulation and product differences

• The selected product contains paroxetine as hydrochloride anhydrous in an immediate-release, off-white uncoated tablet.
• Its excipients are microcrystalline cellulose, calcium hydrogen phosphate dihydrate, croscarmellose sodium, colloidal anhydrous silica and magnesium stearate.
• The selected tablet is essentially sodium-free and does not list lactose among its excipients.

Tablet

Route: Oral

Strengths: 10 mg, 40 mg