Psychiatrymiddle twist
An 84-year-old man with mild Alzheimer disease is brought to the emergency department by his daughter. For two days he has been drowsy after lunch and then agitated by evening, accusing the neighbours of stealing his tools; yesterday morning he was his usual self. His medicines are perindopril, atorvastatin, paracetamol and, since last week, oxybutynin. He is afebrile, pulse 96 beats per minute, blood pressure 118/70 mmHg. He cannot say the months backwards. Which one of the following should be done first?