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What are the Side Effects of Synthroid®?

K.C. Bruning
K.C. Bruning

There are several potential side effects of Synthroid® treatment for hypothyroidism, also known as low thyroid hormone. Most of these symptoms are mild, though there are some severe reactions to the drug that have been reported. The most severe side effects of Synthroid® are the symptoms of an allergic reaction to the drug.

One of the most common side effects of Synthroid® is temporary hair loss. This is most widespread among children who are taking the drug. The loss usually only occurs over the first month of treatment.

Insomnia may be a side effect of synthroid.
Insomnia may be a side effect of synthroid.

Some of other the milder possible side effects of Synthroid® include nausea, stomach cramps, weight loss, or increased appetite. Patients may also experience an increased sensitivity to heat, excessive sweating, or fever. Other symptoms include mental changes such as irritability or nervousness.

There are some patients who may experience diarrhea, vomiting, headache, or a tremor as side effects of Synthroid® treatment. Insomnia and changes in menstrual cycle are also possible. The mild side effects of taking the drug can be discussed with a doctor, but usually only if they become more severe or do not eventually go away on their own.

Chest pains are a severe side effect of Synthroid.
Chest pains are a severe side effect of Synthroid.

Severe side effects that arise from taking Synthroid® should be discussed with a doctor immediately. They include chest pain, which is also known as angina, and an irregular or unusually fast heartbeat. Any signs of an allergic reaction as a result of taking the drug should receive emergency medical attention. These include swelling of the throat, lips, face, or tongue and any kind of breathing problems.

Weight loss can be a side effect of Synthroid.
Weight loss can be a side effect of Synthroid.

There are some conditions which may make taking Synthroid® too risky, or at least require that the patient be observed carefully or take an adjusted dosage while in treatment. The drug is not safe for patients who have or have had adrenal gland problems, a heart attack, or thyrotoxicosis, which is another thyroid disorder. Patients with heart or coronary artery disease, diabetes, anemia, or pituitary gland problems should also speak with a doctor.

Synthroid® is a brand name for the drug levothyroxine. It is also marketed under the names Levothroid®, Levoxyl®, Tirosint® and Unithroid®. The drug is most commonly prescribed for the treatment of hypothyroidism, or low thyroid hormone. It can also be prescribed to treat an enlarged thyroid gland, also known as goiter. The drug works by replacing a hormone that is typically made by the thyroid gland. It helps to ensure the body’s metabolism and energy function properly.

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    • Insomnia may be a side effect of synthroid.
      By: stefanolunardi
      Insomnia may be a side effect of synthroid.
    • Chest pains are a severe side effect of Synthroid.
      By: patpitchaya
      Chest pains are a severe side effect of Synthroid.
    • Weight loss can be a side effect of Synthroid.
      By: forestpath
      Weight loss can be a side effect of Synthroid.