LEVOTHYROXINE (Synthroid) is used for treating low thyroid activity and treating or suppressing different types of goiters. It is also used with surgery and other medicines for managing certain types of thyroid cancer.
Levothyroxine is a thyroid hormone. Thyroid hormones are produced and released by the thyroid gland and regulate the body's metabolism. When the thyroid gland is underactive (hypothyroidism) it does not produce enough thyroid hormone and metabolism slows.
Synthroid
Generic name: Levothyroxine
Levothyroxine capsules
What are levothyroxine capsules?
LEVOTHYROXINE acts as a replacement for people whose thyroid gland does not produce enough thyroid hormone. This medicine can improve symptoms of thyroid deficiency such as slow speech, lack of energy, weight gain, hair loss, dry thick skin and unusual sensitivity to cold. Levothyroxine also helps to treat a condition called goiter, which is an enlarged thyroid gland.
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
- diabetes
- heart disease
- high blood pressure
- low levels of pituitary hormone
- dieting or on a weight loss program
- previous heart attack
- an unusual or allergic reaction to levothyroxine, other thyroid hormones, other medicines, foods, dyes, or preservatives
- pregnant or trying to get pregnant
How should I take this medicine?
Take this medicine by mouth with a full glass of water. Take it on an empty stomach, 30.60 minutes before a meal. Do not crush or cut open the capsules. Follow the directions on the prescription label. Take your doses at regular intervals. Do not take your medicine more often than directed. Do not stop taking except on your doctor's advice.
Talk to your pediatrician regarding the use of this medicine in children. Special care may be needed.
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 drug(s) may interact with this medicine?
- amiodarone
- antacids
- calcium supplements, like Tums® and many others
- carbamazepine
- cholestyramine
- colestipol
- digoxin
- female hormones, including contraceptive or birth control pills
- ketamine
- 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
- soy isoflavones
- sucralfate
- theophylline
- warfarin
Tell your prescriber or health care professional about all other medicines you are taking, including non-prescription medicines, nutritional supplements, or herbal products. Also tell your prescriber or health care professional if you are a frequent user of drinks with caffeine or alcohol, if you smoke, or if you use illegal drugs. These may affect the way your medicine works. Check with your health care professional before stopping or starting any of your medicines.
What side effects may I notice from taking levothyroxine?
Side effects that you should report to your prescriber or health care professional as soon as possible:
- difficulty breathing, wheezing, or shortness of breath
- chest pain
- excessive sweating or intolerance to heat
- fast or irregular heartbeat or pulse rate
- nervousness
- skin rash or hives
- swelling of ankles, feet or legs
Side effects that usually do not require medical attention (report to your prescriber or health care professional if they continue or are bothersome):
- changes in appetite
- changes in menstrual periods
- diarrhea
- fever
- hair loss
- headache
- irritability
- nausea, vomiting
- tremors
- trouble sleeping
- weight loss
What should I watch for while taking this medicine?
If you are taking this medicine for an underactive thyroid, it may be several weeks before you notice an improvement. Check with your doctor if your symptoms do not improve or if you develop any of the above side effects. It may be necessary for you to take this medicine for the rest of your life; do not stop taking except on your doctor's advice.
Do not switch brands of this medicine unless your prescriber agrees with the change. Ask your doctor for advice if you are uncertain.
If you are going to have surgery, tell your doctor that you are taking this medicine.
Where can I keep my medicine?
Keep out of the reach of children.
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 medicine after the expiration date.
What is the shelf life of the pills?
- The expiry date is mentioned on each blister. It is different for different batches. The shelf life is 2 years from the date of manufacture and would differ from batch to batch depending on when they were manufactured.
