Jane is a 53 year old lady who presents with a 1 day history of a left sided headache. There are no neurological symptoms but she feels her colour vision seems a little different. Her only other complaint is that her jaw seems little achey today when chewing. She denies any dental problems.
On examination, cranial nerve and neurological examination are normal. You note some thickening around her left temporal artery.
Based on the likely diagnosis, you decide to start medication before referral to secondary care. What is the most appropriate medication to prescribe as a one-off dose?