Levothyroxine

generic for Euthyrox

Levothyroxine Side Effects

See also Precautions section.

Hair loss may occur during the first few months of treatment. This effect is usually temporary as your body adjusts to this medication. If this effect persists or worsens, tell your doctor or pharmacist promptly.

Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if any of these unlikely but serious effects of high thyroid hormone levels occur: increased sweating, sensitivity to heat, mental/mood changes (such as nervousness, mood swings), tiredness, diarrhea, shaking (tremor), headache, shortness of breath, bone pain, easily broken bones.

Get medical help right away if any of these rare but serious effects of high thyroid hormone levels occur: chest pain, fast/pounding/irregular heartbeat, swelling hands/ankles/feet, seizures.

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.
  • mood changes
  • idiopathic intracranial hypertension
  • hypertension
  • acute myocardial infarction
  • angina
  • cardiac arrest
  • cardiac arrhythmia
  • heart failure
  • irregular menstrual periods
  • menstrual disorder
  • female infertility
  • allergic dermatitis
  • alopecia
  • urticaria
  • muscle spasm
  • muscle weakness
  • osteopenia
  • seizure disorder
  • insomnia
  • fever
  • fatigue
  • hyperhidrosis
  • tremor
  • skin rash
  • flushing
  • weight loss
  • increased appetite
  • headache disorder
  • palpitations
  • dyspnea
  • vomiting
  • diarrhea
  • abdominal pain with cramps
  • abnormal hepatic function tests
  • nervousness
  • angioedema
  • irritability
  • symptoms of anxiety
  • heat intolerance
  • tachycardia
  • increased pulse rate

Drug Interactions

See also How to Use Section.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: "blood thinners" (such as warfarin), digoxin, sucroferric oxyhydroxide.