A nurse is caring for an 82-year-old male with a history of mild kidney dysfunction who is recently admitted to the hospital for an unwitnessed fall. The nurse noted that the client had been taking cimetidine (Tagamet HB) at the maximum dosage for 2 months. Which of the following are complications of this cimetidine (Tagamet HB) that contributed to his admission? (Select All That Apply.)