Levothyroxine (Injection)


Levothyroxine (lee-voe-thye-ROX-een)
Treats hypothyroidism (underactive thyroid).

Brand Name(s)

There may be other brand names for this medicine.

When This Medicine Should Not Be Used

You should not use this medicine if you have had an allergic to levothyroxine. You should not receive this medicine if you have adrenal gland problems (Addison's disease, adrenal cortical insufficiency) that have not been treated yet. You should not receive this medicine if you have an overactive thyroid gland (hyperthyroid, Grave's disease, thyrotoxicosis) that has not be treated yet.

How to Use This Medicine

  • Your doctor will prescribe your exact dose and tell you how often it should be given. This medicine is given through a needle placed in your vein or in one of your muscles.
  • A nurse or other trained health professional will give you this medicine.

Drugs and Foods to Avoid

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.
  • Make sure your doctor knows if you are using blood thinners such as warfarin (Coumadin®).
  • Make sure your doctor knows if you are using medicines such as epinephrine or norepinephrine.

Warnings While Using This Medicine

  • Make sure your doctor knows if you are pregnant or breast feeding. Make sure your doctor knows if you have heart disease, diabetes, or if you have adrenal gland problems (Addison's disease, adrenal cortical insufficiency).

Possible Side Effects While Using This Medicine

Call your doctor right away if you notice any of these side effects:
  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing.
  • Fast or pounding heartbeat, uneven heartbeat, or chest tightness.
  • Severe diarrhea.
  • Trouble breathing.
If you notice these less serious side effects, talk with your doctor:
  • Anxiety, confusion, or headache.
  • Difficulty sleeping.
  • Increased sweating of your hands or feet.
  • Irregular or decreased menstrual bleeding.
  • Loss of appetite, weight loss.
  • Tiredness.
  • Tremors.

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088
Review Date: 2011-02-04 Reviewed By: Keywords: ,
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