INS and type 2 diabetes mellitus: In an experimental study, hydroxychloroquine significantly elevated insulin-blood concentration resulting in reduced glucose levels in a concentration dependent fashion in diabetic rats.[7] Clinically, hydroxychloroquine showed improvement in sulphonylurea refractory patients with poorly controlled Type 2 diabetes.[8] In another prospective, multicentric observational study of 4905 adults with rheumatoid arthritis, diabetes was reported in 54 patients who had taken hydroxychloroquine as compared to 171 patients who had never taken hydroxychloroquine.