LEVOTHYROXINE (lee voe thye ROX een) treats low thyroid levels (hypothyroidism) in your body. It works by replacing a thyroid hormone normally made by the body. Thyroid hormones play an important role in your overall health. They help support metabolism and energy levels.
What should I tell my care team before I take this medication?
They need to know if you have any of these conditions:
Addison's disease or other adrenal gland problem
Dieting or on a weight loss program
High blood sugar (diabetes)
Pituitary gland problem
Take medications that treat or prevent blood clots
An unusual or allergic reaction to levothyroxine, thyroid hormones, other medications, foods, dyes, or preservatives
Pregnant or trying to get pregnant
How should I use this medication?
Take this medication by mouth with plenty 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, sevelamer, lanthanum, or sucralfate within 4 hours of taking this medication. Follow the directions on the prescription label. Take at the same time each day. Do not take your medication more often than directed.
Contact your care team regarding the use of this medication in children. While this medication may be prescribed for children and infants as young as a few days of age for selected conditions, precautions do apply. For infants, you may crush the tablet and place in a small amount of (5 to 10 mL or 1 to 2 teaspoonfuls) of water, breast milk, or non-soy based infant formula. Do not mix with soy-based infant formula. Give as directed.
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 medication?
Certain medications for depression
Certain medications to treat cancer
Female hormones, like estrogens and birth control pills, patches, rings, or injections
Liquid nutrition products like Ensure
Medications for colds and breathing difficulties
Medications for diabetes
Medications for hyperthyroidism
Medications or dietary supplements for weight loss
Phenobarbital or other barbiturates
Sodium polystyrene sulfonate
Steroid medications like prednisone or cortisone
What side effects may I notice from receiving this medication?
Side effects that you should report to your care team as soon as possible:
Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
Excessive sweating or sensitivity to heat
Heart palpitations—rapid, pounding, or irregular heartbeat
Heart rhythm changes—fast or irregular heartbeat, dizziness, feeling faint or lightheaded, chest pain, trouble breathing
Irregular menstrual cycles or spotting
Tremors or shaking
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Changes in appetite
What should I watch for while using this medication?
Be sure to take this medication with plenty of fluids. Some tablets may cause choking, gagging, or difficulty swallowing from the tablet getting stuck in your throat. Most of these problems disappear if the medication is taken with the right amount of water or other fluids.
Do not switch brands of this medication unless your care team 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 medication for an underactive thyroid, it may be several weeks before you notice an improvement. Check with your care team if your symptoms do not improve.
It may be necessary for you to take this medication for the rest of your life. Do not stop using this medication unless your care team advises you to.
This medication 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 care team that you are taking this medication.
Where should I keep my medication?
Keep out of the reach of children and pets.
Store at room temperature between 15 and 30 degrees C (59 and 86 degrees F). Protect from light and moisture. Keep container tightly closed. Throw away any unused medication after the expiration date.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.
This information is educational only and should not be construed as specific instructions for individual patients nor as a substitute for medical advice, diagnosis or treatment. Talk to your health care provider or pharmacist about the information and instructions. K Health assumes no liability for any use or reliance on this information.