Under-the-counter acquired acute coronary syndrome: Methaemoglobinaemia.

A 73-year-old male suffers a type-2 inferior myocardial infarction and is found unconscious, hypotensive and centrally cyanotic. His arterial blood gas analysis shows a chocolate-brown discoloration, with pO2 45.1 kPa, HbO2 48.9%, MetHb 51%, BE -9 and a lactate of 3.7 mmol/l. Administration of 200 mg of methylene blue intravenously, normalizes the patient's abnormalities. His life-threatening acquired methaemoglobinaemia appears secondary to under-the-counter viagra.