Synthroid Side Effects

Although most people have no problems when taking Synthroid, side effects are possible. Examples of common side effects include heart palpitations, difficulty breathing, and chest pain. Because some of these side effects can be quite dangerous, be sure to immediately report any side effects of Synthroid to your healthcare provider, as he or she may need to adjust your dosage.

 

An Introduction to Synthroid Side Effects

As with any medicine, side effects are possible with Synthroid® (levothyroxine sodium). However, not everyone who takes the drug will experience side effects. In fact, most people tolerate it quite well.
 
(This article covers many, but not all, of the possible side effects with Synthroid. Your healthcare provider can discuss a more complete list of Synthroid side effects with you.)
 

Possible Synthroid Side Effects

Synthroid side effects typically occur when the dose is too high. Too much thyroid hormone causes symptoms of an overactive thyroid (hyperthyroidism). Some of these symptoms can be quite dangerous, and any of these symptoms should be reported to your healthcare provider, as they may signal that your Synthroid dosage needs to be adjusted. These side effects include:
 
As with any medication, Synthroid can also cause allergic reactions. Seek medical attention immediately if you develop signs of an allergic reaction, including:
 
  • An unexplained rash
  • Hives
  • Itching
  • Unexplained swelling (especially of the lips, mouth, or throat).
 
(Synthroid Side Effects Continued: Page 2)
Written by/reviewed by: Kristi Monson, PharmD; Arthur Schoenstadt, MD
Last reviewed by: Kristi Monson, PharmD;