What are Synthroid (levothyroxine) side effects?

Some of the common side effects of Synthroid are listed below. Call your doctor if these side effects are severe or do not go away after a few days.

•  Shakiness
• Racing heart
• Fever
• Sweating
• Diarrhea
• Vomiting
• Changes in appetite
• Weight loss
• Hair loss
• Muscle weakness
• Fatigue
• Heat sensitivity
• Anxiety
• Problems with sleeping
• Changes in menstrual cycle

 Some of the adverse effects of Synthroid can be more serious. Please call your doctor right away if you experience any of the following side effects:

•  Shortness of breath
• Wheezing
• Swelling of the hands, feet, ankles, or lower legs 
• Hives, itching, rash, flushing
• Stomach pain, nausea

The above list may not include all the potential side effects of Synthroid. You can also report unusual side effects to the Food and Drug Administration at 1-800-FDA-1088.

Synthroid overdose: Call your doctor right away or go to the nearest emergency room in case of a known or suspected overdose. If a person cannot be awakened, has had a seizure, or has trouble breathing, call 911 immediately. Symptoms of Synthroid overdose may include chest pain, irregular or rapid heartbeat, uncontrolled shaking, anxiety, nervousness, irritability, excessive sweating, problems with sleep, confusion, shortness of breath, loss of consciousness, and seizures.

 NOTE: Synthroid is a prescription drug intended to be used only by you. Never share your medication with others or use someone else’s Synthroid.

 Source: FDA