Hello Travis, Welcome to HCM. I am Dr Mbong. The most common side effect of Arimedex is bone pain. The medication s side effects depend on the dose you are on: the higher the dose, the more the side-effect. You will need to ask the physician who prescribed it for Biphosphonate and Calcium tablet prescriptions, which will reduce the occurence of bone pain. In some people taking Arimedex has even been associated in the long run with bone fractures, so be careful about strainous physical activity on it. Arimedex works by inhibiting circulating blood levels of estrogens, a hormone (which not only women have but also men though in relatively smaller amounts). Inihbiting estrogens may among other effects like on the bone, may cause a decline in the immune protective mechanisms of the body, cause a cough and may make you more susceptible to germs which may explain the fever. I advise you see your physician for the above adjuvant medication prescriptions I proposed and for a work up to determine if the fever and cough are of infectious origin. You may also need a reduction in the dose you are on (which should take into considertion your weight) for Arimedex s side-effects are dose dependent. All the best.