I took hydroxychloroquine for two years. A long time ago as a visiting cancer surgeon in Asia, in Thailand, Nepal, India, and Bangladesh. From 1987 to 1990. Malaria is rife there. I took it for prophylaxis, 400 milligrams once a week for two years. Never had any trouble. It was inexpensive and effective. I started it two weeks before and was supposed to continue it through my stay and four weeks after returning. But I stopped it after two years. I was worried about potential side effects of which there are many, as with all drugs right down to Tylenol...