19th June 2023

A 40-year-old-man presents to A&E with severe headaches of his right temporal area

A 40-year-old-man presents to A&E with severe headaches of his right temporal area, associated with redness and tearing of his right eye, and rhinorrhoea. He reports 18 similar episodes today, lasting a few minutes each. He has received IV paracetamol 3 hours ago yet continues to have severe pain. He has no significant past medical history and takes no regular medication. On examination, he has congestion of his right eye, but there is no focal neurology. Blood investigations, including ESR, are normal.

Given the likely diagnosis, which of the following is the most appropriate treatment to prevent further attacks?