The Ciprofloxacin 500 mg were ordered to be taken twicw a day. The Marines were the only service that I know for sure were given these orders. We were ordered to start them before the air war, and the order to stop taking them was giver at 0645 Feb 28th 1991 by General Myatt 1st Marine div commander. We were forced to take Cipro 500mg twice a day for 40 plus days. so the Marines were given NAPP (nerve agent protection pills) or pyridiostigmine bromide to protect us from nerve agent, and We were ordered to take the Cipro to protect from anthrax. We were part of the human research trial conducted by the Bayer corporation in the creation of their new anthrax pills. At that time they had no idea of the side effects of flouroquinolones. Thats the class of medications that Cipro falls into. After the Gulf War the FDA and Bayer co. started releasing the list of side effects.You do need to know what was done to you so you will have to do your own research. Good luck to all of you and Semper Fi.