1 What is Synthroid?

Brand: Synthroid

Generic: Levothyroxine Sodium

Synthroid is a synthetic thyroid hormone. It is chemically identical to thyroxine (T4). It is used to treat hypothyroidism, a condition in which thyroid does not produce enough amount of this hormone (T4) on its own.

Synthroid injection is used when a rapid effect is required and when oral route is not allowed. It is available in the form of powder for solution, only with your doctor’s prescription.

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2 What to Know Before Using

If you are about to start Synthroid, speak with your doctor about what you need to know.

Before starting the treatment your doctor should be informed about conditions such as:

Allergy: Inform your doctor if you are allergic to any food, preservatives, dyes, or had an allergic reaction when you used this drug before.

Children: There are no adequate studies done which prove Levothyroxine harmful effects in children. Use it after consulting your doctor.

Elderly: They are more sensitive to its effects. The elderly patient should use it with caution. Your doctor may adjust your dose if you have any age-related heart or blood vessels problem.

Pregnancy: It is a category A drug. It is safe in pregnancy. It causes no harm to an unborn baby. Inform your doctor that you are pregnant he may want to increase your dose.

Breast Feeding: Levothyroxine can pass into breast milk, but cause no harm to the baby. Inform your doctor about breastfeeding, he may change your dose of Levothyroxine during breastfeeding.

Drug Interactions: Levothyroxine interacts with many drugs. It should not be used with several drugs. Your doctor should be informed of any other medicine which you are taking as he/she may change your drug or dosage.

Other Medical Problem: Several other conditions may reduce its effectiveness.

Make sure you inform your doctor of conditions such as:

  • Thyrotoxicosis (thyroid disorder).
  • If recently received radiation therapy with iodine such as (I-131).
  • Heart disease, coronary artery disease, or a history of blood clots.
  • Diabetes (insulin or oral diabetes medication doses may need to be changed when you start taking Levothyroxine).
  • Anemia (lack of red blood cells).
  • Untreated or uncontrolled adrenal gland disorder.
  • If you have recently had a heart attack or are having any symptoms of a heart attack (chest pain, pain spreading to the jaw or shoulder, nausea, sweating, general ill feeling).
  • Osteoporosis.
  • Pituitary gland problems: Use with caution. May make these conditions worse.

3 Proper Usage

To use Synthroid properly, you must follow all instructions given by your doctor. Drug dose is different for different people based on body weight.

The following information is an average dose of this drug. For injection forms:

  • Adult: 50 to 100 micrograms (mcg) is given by injection into muscle or veins once a day.
  • Children: The dose is based on body weight and must be determined by your doctor.

4 Precautions to Take

Before using Synthroid, there are some precautions you must take. You should go to your doctor for a regular checkup. Your doctor may alter your dose according to your needs.

It should not be used for the treatment of obesity or weight loss. It is not helpful in reducing weight. It can cause serious harm if taken in large doses.

5 Potential Side Effects

Make sure you meet with your doctor in using Synthroid to avoid unwanted potential side effects. Some people may experience none or minor side effects.

Consult with your doctor if they become problematic or frequent:

More common are:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

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