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 disease
Adrenal gland problem
Bone problems
Chest pain
Diabetes
Dieting or on a weight loss program
Fertility problems
Heart disease
Pituitary gland problem
Take medications that treat or prevent blood clots
An unusual or allergic reaction to levothyroxine, other medications, foods, dyes, or preservatives
Pregnant or trying to get pregnant
Breastfeeding
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?
Amiodarone
Antacids
Calcium supplements
Carbamazepine
Certain medications for depression
Certain medications to treat cancer
Cholestyramine
Clofibrate
Colesevelam
Colestipol
Digoxin
Estrogen or progestin hormones
Iron supplements
Ketamine
Lanthanum
Liquid nutrition products, such as Ensure
Lithium
Medications for colds and breathing difficulties
Medications for diabetes
Medications or dietary supplements for weight loss
Methadone
Niacin
Orlistat
Oxandrolone
Phenobarbital or other barbiturates
Phenytoin
Rifampin
Sevelamer
Simethicone
Sodium polystyrene sulfonate
Soy isoflavones
Steroid medications, such as prednisone or cortisone
Sucralfate
Testosterone
Theophylline
Thyroid hormones
Warfarin
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
Anxiety, nervousness
Excessive sweating or sensitivity to heat
Fever
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
Severe diarrhea
Tremors or shaking
Trouble sleeping
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
Changes in appetite
Hair loss
Headache
Nausea
Vomiting
What should I watch for while using this medication?
Visit your care team for regular checks on your progress. Tell your care team if your symptoms do not start to get better or if they get worse. It may be some time before you see the benefit from this medication.
Do not switch brands of this medication unless your care team agrees with the change. Ask questions if you are uncertain.
You may need blood work done while you are taking this medication.
Biotin (vitamin B7) may interfere with your thyroid function test. Stop taking supplements that contain biotin 2 days before your blood work.
This medication can affect blood sugar levels. If you have diabetes, check your blood sugar as directed.
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.
