A 78 year old man who lives alone is brought in confused and disoriented.

He was supposedly normal one week ago, after which he started feeling generally unwell, with a poor appetite. He also experienced several episodes of nausea and vomiting.

He is on treatment for stable ischemic heart disease and atrial fibrillation with Telmisartan, Bisoprolol, Rosuvastatin, Digoxin and Warfarin.

A full blood count, urinalysis and chest X-ray are normal. His INR is 2.0