Megestrol acetate

How it works

It exerts progestogenic and anti-oestrogenic effects on hormone-sensitive tissue and stimulates appetite through incompletely understood central and metabolic actions.

Prescribing in practice

• It increases the risk of venous thromboembolism, so assess thrombotic risk and remain alert to signs of clotting during treatment.
• Prolonged use can suppress the adrenal axis, and abrupt withdrawal after long courses may unmask adrenal insufficiency.
• Avoid in pregnancy and use with caution in patients with a history of thromboembolic disease or diabetes.

Monitoring

Monitor weight, glycaemic control, blood pressure and for symptoms of thromboembolism or adrenal suppression during prolonged therapy.

Counselling the patient

• Report leg swelling or pain, breathlessness or chest pain promptly.
• Do not stop long-term treatment suddenly without medical advice.
• Weight gain is an expected and sometimes intended effect when used for appetite.

Evidence & guidelines

Megestrol acetate is an established hormonal option in advanced breast and endometrial cancer and for appetite stimulation in cachexia, as reflected in oncology practice and the SPC.