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Levothroid

Last reviewed on RxList: 1/26/2017
Levothroid Side Effects Center

Last reviewed on RxList 12/13/2016

Levothroid (levothyroxine sodium) is a replacement for a hormone that is normally produced by your thyroid gland to regulate the body's energy and metabolism used to treat hypothyroidism (low thyroid hormone). Levothroid is also used to treat or prevent goiter (enlarged thyroid gland), which can be caused by hormone imbalances, radiation treatment, surgery, or cancer. Common side effects of Levothroid include:

  • hair loss during the first few months of treatment. This side effect is usually temporary as your body adjusts to Levothroid.

Contact your doctor if you experience serious side effects of Levothroid including:

  • headache,
  • sleep problems (insomnia),
  • feeling nervous or irritable,
  • fever,
  • hot flashes,
  • sweating,
  • pounding heartbeats or fluttering in your chest,
  • changes in your menstrual periods,
  • appetite changes, or
  • weight changes.

For adult hypothyroidism, Levothroid is started at 12.5-125 mcg/day taken orally. Dose may differ with individuals based on age, the presence of cardiovascular disease, tolerance, side effects, and blood levels of thyroid hormone. It may take one to three weeks before effects are seen. Levothroid may interact with calcium carbonate, ferrous sulfate iron supplement, sucralfate, sodium polystyrene sulfonate, antacids that contain aluminum, and cholesterol-lowering drugs. Tell your doctor all medications or supplements you are taking. Current information shows that Levothroid may be used during pregnancy. Tell your doctor if you are pregnant as your dose may need to be adjusted. This medication passes into breast milk but is unlikely to harm a nursing infant. Consult your doctor before breastfeeding.

Our Levothroid (levothyroxine sodium) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Levothroid Consumer Information

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have a serious side effect such as:

  • headache;
  • sleep problems (insomnia);
  • feeling nervous or irritable;
  • fever, hot flashes, sweating;
  • pounding heartbeats or fluttering in your chest;
  • changes in your menstrual periods; or
  • appetite changes, weight changes.

Less serious side effects may include mild hair loss.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Read the entire detailed patient monograph for Levothroid (Levothyroxine Sodium)

Levothroid Professional Information

SIDE EFFECTS

Adverse reactions associated with levothyroxine therapy are primarily those of hyperthyroidism due to therapeutic overdosage (see PRECAUTIONS and OVERDOSAGE). They include the following:

General: fatigue, increased appetite, weight loss, heat intolerance, fever, excessive sweating;

Central nervous system: headache, hyperactivity, nervousness, anxiety, irritability, emotional lability, insomnia;

Musculoskeletal: tremors, muscle weakness;

Cardiovascular: palpitations, tachycardia, arrhythmias, increased pulse and blood pressure, heart failure, angina, myocardial infarction, cardiac arrest;

Respiratory: dyspnea;

Gastrointestinal: diarrhea, vomiting, abdominal cramps and elevations in liver function tests;

Dermatologic: hair loss, flushing;

Endocrine: decreased bone mineral density; Reproductive: menstrual irregularities, impaired fertility.

Pseudotumor cerebri and slipped capital femoral epiphysis have been reported in children receiving levothyroxine therapy. Overtreatment may result in craniosynostosis in infants and premature closure of the epiphyses in children with resultant compromised adult height.

Seizures have been reported rarely with the institution of levothyroxine therapy.

Inadequate levothyroxine dosage will produce or fail to ameliorate the signs and symptoms of hypothyroidism.

Hypersensitivity reactions to inactive ingredients have occurred in patients treated with thyroid hormone products. These include urticaria, pruritus, skin rash, flushing, angioedema, various GI symptoms (abdominal pain, nausea, vomiting and diarrhea), fever, arthralgia, serum sickness and wheezing. Hypersensitivity to levothyroxine itself is not known to occur.

Read the entire FDA prescribing information for Levothroid (Levothyroxine Sodium)

Related Resources for Levothroid

Read the Levothroid User Reviews »

© Levothroid Patient Information is supplied by Cerner Multum, Inc. and Levothroid Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.

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