Exemestane: Uses, Safety and Drug Interactions

Exemestane: uses, safety and drug interactions

Overview: Exemestane is an oral aromatase inhibitor used in specialist breast cancer treatment. It reduces oestrogen formation by a different chemical mechanism from some other drugs in the same therapeutic class. The information here follows the UK Viatris product document for film-coated tablets and should be read together with the actual prescribed product instructions.

Uses and formulation: The UK label includes adjuvant treatment of postmenopausal women with oestrogen receptor-positive invasive early breast cancer after two to three years of initial tamoxifen treatment. It also includes selected advanced breast cancers that have progressed after anti-oestrogen treatment. These decisions depend on the tumour, menopause status and earlier treatment. This page is not an instruction to combine hormonal cancer medicines or use them for fertility or athletic purposes.

Safety: Exemestane is contraindicated before menopause, during pregnancy and while breastfeeding. Common problems include hot flushes, joint or muscle symptoms, fatigue, headache and nausea. Bone mineral density can fall, so fracture risk and vitamin D status need clinical attention. Seek urgent assessment for serious allergic symptoms or a severe widespread rash; promptly report jaundice, dark urine or other possible liver symptoms.

Drug interactions: Rifampicin, phenytoin and carbamazepine can lower exemestane exposure and may reduce effectiveness. A pharmacokinetic study with rifampicin demonstrated reduced drug exposure, but did not establish the size of a cancer-outcome effect. Oestrogen-containing medicines can oppose the treatment and should not be coadministered. Give the oncology team a complete medicine and supplement list; do not compensate for an interaction by changing a dose yourself.

Sources

• Viatris Exemestane 25 mg film-coated tablets, UK SmPC

This page provides an English summary of the cited sources. Source check: 30 October 2026. This date records a source check, not a clinical review by a doctor or pharmacist. Follow the current leaflet for your product and seek professional advice for personal treatment.