Health Guide

Levothyroxine (By injection)

Levothyroxine (lee-voe-thye-ROX-een)

Treats severe hypothyroidism.

Brand Name(s):

PremierPro Rx Levothyroxine Sodium, levothyroxine sodium Novaplus

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is generally considered safe for most people. Talk to your doctor if you have concerns.

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 muscle.
  • A nurse or other health provider 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.

  • Some medicines can affect how levothyroxine works. Tell your doctor if you are using any of the following:
    • A blood thinner, such as warfarin
    • Digitalis
    • Medicine for diabetes
    • Medicine for depression, such as amitriptyline, maprotiline, or sertraline

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have heart disease, diabetes, pernicious anemia, or adrenal gland problems.

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, pounding, or uneven heartbeat
  • Chest pain that may spread, trouble breathing, nausea, unusual sweating, fainting

If you notice these less serious side effects, talk with your doctor:

  • Appetite changes or weight loss
  • Nervousness, difficulty sleeping
  • Sweating, intolerance to heat
  • 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

Last Updated: 7/4/2018
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