Levothyroxine (Synthroid®) Side Effects for Hypothyroidism

As the most prescribed drug in the United States, levothyroxine for hypothyroidism doesn't come without side effects.

What Exactly is Levothyroxine?

Levothyroxine is a prescription medication used to treat underactive thyroid or hypothyroidism. It is available under the brand names Synthroid®, Unithroid®, Levothroid®, Levoxyl®, Levo-T®, and Tirosint®. These synthetic medications will replace or provide your body with thyroid hormone that is not being produced naturally.

Levothyroxine is the most prescribed drug in the United States with more than 123 million prescriptions written every year, despite some controversy over whether it actually helps people taking the medicine. Available since the 1950s, Levothyroxine was not approved by the United States Food and Drug Administration (FDA) until the year 2000.

What are the Dangers of Levothyroxine?

While Levothyroxine can help reduce hypothyroid symptoms, it does not come without side effects or warnings. It’s also not a cure for the condition. Most doctors will tell you that you will have to take this synthetic drug for the rest of your life to feel healthy. However, studies have shown that taking levothyroxine can actually make you feel sick and cause other diseases.

Side Effects of Levothyroxine

Following are common side effects of levothyroxine:

  • Increased appetite
  • Weight gain
  • Stomach cramps
  • Nausea and vomiting
  • Diarrhea
  • Menstrual cycle changes (in women)
  • Tremor
  • Fever
  • Excessive sweating
  • Nervousness, irritability
  • Insomnia
  • Headache
  • Temporary hair loss (in beginning of treatment)

More serious side effects may include:

  • Chest pain
  • Rapid or irregular heartbeat or pulse

Warnings of Levothyroxine

It goes without saying that a combination of drugs can have adverse side effects. Levothyroxine is no different, and all manufacturing brands address warnings about the drug. Many studies have also shown long-term side effects from using levothyroxine that may be irreversible:

Adverse Side Effects from Prescription Misuse:Any medications taken with levothyroxine may have severe side effects or even cause death, including those taken for heart disease, diabetes, blood clotting problems, and adrenal or pituitary gland problems. Blood sugar levels or glucose in the urine may be destabilized in those with diabetes. Individuals taking blood thinning medications may also have to be checked often. Additionally, levothyroxine is sometimes prescribed for weight loss with no hypothyroidism diagnosis, and this may result in serious or even life-threatening situations – especially if used in combination with other appetite suppressants.

Bone Loss: According to a study published in the Journal of Research in Pharmacy Practice, bone loss or osteoporosis is significantly greater in patients taking levothyroxine and who have been diagnosed with primary hypothyroidism.

Cardiovascular Issues: Long-term levothyroxine treatment is associated with cardiovascular effects in young adults with congenital hypothyroidism, specifically impaired diastolic function, exercise capacity, and increased intima-media thickness. Levothyroxine plays a major role in long-term cardiovascular risk, particularly coronary heart disease and ischemic stroke, as well as in patients who have received a thyroidectomy.

Central Nervous System Problems: A study published by The Journal of Clinical Endocrinology & Metabolism noted that women receiving levothyroxine had decrements in health status and mood compared to healthy controls.

Making the Right Choice for Your Hypothyroid Condition

If you’ve recently been diagnosed with hypothyroidism or goiter, your doctor may insist you take levothyroxine. That is completely your choice. However, if you’re not sure about taking the synthetic drug, you may want to talk with a practitioner in alternative medicine who can devise a proper treatment plan for you as your thyroid will need to be monitored on a regular basis.

If you want to learn more about natural therapy for your thyroid condition, check out this article: Natural Therapy for Hypothyroidism.