 [ Symptoms ] is a person covered if they got an expired flu shot should they get another one [ Disease ] while it is extremely rare to be allergic to synthroid generic name levothyroxine that does not mean it is impossible synthroid is a brand name it contains certain binders and dyes that could conceivably cause an allergic reaction even though this medication has been used safely by millions of people rest assured if it turns out you are allergic to something in synthroid there are plenty of other options for you generic versions of levothyroxine abound your health care provider certainly can let you try different preparations to see which one works for you without causing an allergic reaction however it is also possible something else entirely is causing your problems you should see your health care provider as soon as possible to try to determine what is causing your symptoms i hope you feel better soon