Drugs A - Z

Levothyroxine Sodium Oral capsule

This medicine can improve symptoms of thyroid deficiency such as slow speech, lack of energy, weight... more

Generic Name: Tirosint

What is this medicine?

LEVOTHYROXINE (lee voe thye ROX een) is a thyroid hormone. This medicine can improve symptoms of thyroid deficiency such as slow speech, lack of energy, weight gain, hair loss, dry skin, and feeling cold. It also helps to treat goiter (an enlarged thyroid gland). It is also used to treat some kinds of thyroid cancer along with surgery and other medicines.

What should I tell my health care provider before I take this medicine?

They need to know if you have any of these conditions:
  • angina
  • blood clotting problems
  • diabetes
  • dieting or on a weight loss program
  • fertility problems
  • heart disease
  • high levels of thyroid hormone
  • pituitary gland problem
  • previous heart attack
  • an unusual or allergic reaction to levothyroxine, thyroid hormones, other medicines, foods, dyes, or preservatives
  • pregnant or trying to get pregnant
  • breast-feeding

How should I use this medicine?

Take this medicine by mouth with a glass of water. It is best to take on an empty stomach, at least 30 minutes to one hour before breakfast. Avoid taking antacids containing aluminum or magnesium, simethicone, bile acid sequestrants, calcium carbonate, sodium polystyrene sulfonate, ferrous sulfate, and sucralfate within 4 hours of taking this medicine. Do not cut, crush or chew this medicine. Follow the directions on the prescription label. Take at the same time each day. Do not take your medicine more often than directed.

Talk to your pediatrician regarding the use of this medicine in children. While this drug may be prescribed for selected conditions, precautions do apply. Since the capsules cannot be crushed or placed in water, they may only be given to infants and children who are able to swallow an intact capsule.

Overdosage: If you think you've taken too much of this medicine contact a poison control center or emergency room at once.

What if I miss a dose?

If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.

What may interact with this medicine?

  • amiodarone
  • antacids
  • anti-thyroid medicines
  • calcium supplements
  • carbamazepine
  • cholestyramine
  • colestipol
  • digoxin
  • female hormones, including contraceptive or birth control pills
  • iron supplements
  • ketamine
  • liquid nutrition products like Ensure
  • medicines for colds and breathing difficulties
  • medicines for diabetes
  • medicines for mental depression
  • medicines or herbals used to decrease weight or appetite
  • phenobarbital or other barbiturate medications
  • phenytoin
  • prednisone or other corticosteroids
  • rifabutin
  • rifampin
  • simethicone
  • sodium polystyrene sulfonate
  • soy isoflavones
  • sucralfate
  • theophylline
  • warfarin

What should I watch for while using this medicine?

Do not switch brands of this medicine unless your health care professional agrees with the change. Ask questions if you are uncertain.

You will need regular exams and occasional blood tests to check the response to treatment. If you are receiving this medicine for an underactive thyroid, it may be several weeks before you notice an improvement. Check with your doctor or health care professional if your symptoms do not improve.

It may be necessary for you to take this medicine for the rest of your life. Do not stop using this medicine unless your doctor or health care professional advises you to.

This medicine can affect blood sugar levels. If you have diabetes, check your blood sugar as directed.

You may lose some of your hair when you first start treatment. With time, this usually corrects itself.

If you are going to have surgery, tell your doctor or health care professional that you are taking this medicine.


Last Updated: March 11, 2010
Licensed from
The Healthline Site, its content, such as text, graphics, images, search results, HealthMaps, Trust Marks, and other material contained on the Healthline Site ("Content"), its services, and any information or material posted on the Healthline Site by third parties are provided for informational purposes only. None of the foregoing is a substitute for professional medical advice, examination, diagnosis, or treatment. Always seek the advice of a physician or other qualified healthcare provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on the Healthline Site. If you think you may have a medical emergency, call your doctor or 911 immediately. Please read the Terms of Service for more information regarding use of the Healthline Site.
Advertisement