Raymond is a 28 year old engineer who presented with a one month history of well-defined scaly erythematous plaques on his knees and elbows. The appearance is classic of Psoriasis. Past medical history includes Anxiety, Migraines and Irritable bowel syndrome. He takes regular Propranolol, Mebeverine and Sumatriptan along with Paracetamol and Movicol when required.
Which one of his medications should you counsel him could trigger his Psoriasis?