ABSTRACT: BACKGROUND: Pituitary apoplexy is a life-threatening endocrine emergency that is caused by haemorrhage or infarction of the pituitary gland, commonly within a pituitary adenoma. Patients classically present with headache, ophthalmoplegia, visual field defects and altered mental state, but may present with a typical symptoms such as fever and altered conscious level. CASE PRESENTATION: A 57-year-old female with a known pituitary macroadenoma was treated for suspected acute coronary syndrome with aspirin, clopidogrel and full dose enoxaparin. She developed a severe and sudden headache, nausea and vomiting and visual deterioration. A CT scan showed haemorrhage into the pituitary macroadenoma. She underwent neurosurgical decompression. Post-operatively her visual fields and acuity returned to baseline. She was continued on hydrocortisone and thyroxine replacement on discharge. CONCLUSION: This case illustrates the risks of anticoagulation in a patient with a known pituitary macroadenoma, and raises the issue of whether these tumours present a relative contraindication to the use of dual antiplatelet and anticoagulation in acute coronary syndrome.