A 72-year man having lung carcinoma had a very high blood sugar post-pneumonectomy. Stress related. He was immediately prescribed anti-diabetic agent. He visited his family doctor and was given saxagliptin 5mg od. He feels hypoglycemic often. He takes theophylline for bronchodilation.

What is the prerogative of this medicine over metformin as first line of treatment. Also is it safe in elderly patients. He has frequent bouts of hypoglycemia. Monthly pps is 126-150 for past 1 year. Kindly give your suggestions.