What should I watch for while taking Synthroid ?
If you are taking this medicine for an underactive thyroid, it may be several weeks before you notice an improvement. Check with your doctor if your symptoms do not improve or if you develop any of the above side effects. It may be necessary for you to take this medicine for the rest of your life; do not stop taking except on your doctor’s advice. Do not switch brands of this medicine unless your prescriber agrees with the change. Ask your doctor for advice if you are uncertain.