Thyrox contains levothyroxine, a synthetic hormone that replaces what the thyroid gland cannot make. Side effects are rarely caused by the drug itself; instead, they usually indicate that the current dosage is either too high or too low. Because levothyroxine is the standard treatment, there isn't a direct alternative with fewer side effects. The best approach is to consult her doctor, who will likely order a simple thyroid function blood test. Adjusting her generic levothyroxine dose based on these results usually resolves the side effects completely. Please do not alter or stop her medication without consulting her physician.