toremifene citrate: clinical use

Prescribing considerations

• Confirm hormone-dependent metastatic disease and postmenopausal status.
• Review cardiac history, QT-prolonging medicines and correctable electrolyte disturbances.
• Use cautiously in hepatic impairment; renal impairment did not significantly alter pharmacokinetics.
• Generally avoid use in patients with previous severe thromboembolic disease.
• Assess endometrial risk factors and lactose-related contraindications.

Contraindications and cautions

• Hypersensitivity to toremifene or an excipient
• Pre-existing endometrial hyperplasia or severe hepatic failure in long-term use
• Congenital or documented acquired QT prolongation
• Uncorrected hypokalaemia
• Clinically relevant bradycardia
• Clinically relevant heart failure with reduced left-ventricular ejection fraction
• Previous symptomatic arrhythmias
• Concurrent QT-prolonging medicines

Monitoring

• Perform gynaecological assessment before treatment and at least annually.
• Monitor red-cell, white-cell and platelet counts.
• Review for liver injury, particularly during the first months.
• Monitor calcium closely at treatment initiation in patients with bone metastases.
• Stop treatment and obtain an ECG if symptoms suggesting arrhythmia develop.

Clinical pharmacology

Toremifene is a non-steroidal triphenylethylene selective oestrogen receptor modulator. It is mainly metabolised by CYP3A and eliminated slowly, chiefly as metabolites in faeces.

Formulation and product differences

• The selected presentation is a white, immediate-release oral tablet supplied in blister packaging.
• The formulation contains lactose and is essentially sodium-free.

Tablet

Route: Oral

Strengths: 60 mg