1 What is Levothyroid?

Brand: Levothyroid, Levoxyl, Synthroid, Tirosint, Unithyroid

Generic: Levothyroxine

Levothyroid 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.

It is also used to treat goiter (enlarged thyroid gland) which is caused by hormonal imbalance, radiation, surgery, cancer.

It is available in the form of tablet or capsule, only with your doctor’s prescription.

2 What to Know Before Using

Before using Levothyroid, you must know all about the risks and complications associated with it.

Before starting the treatment your doctor should be informed about condition 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 cautiously. Your doctor may adjust your dose if you have any age-related heart or blood vessels problem.

Pregnancy: Levothyroxine is a category a drug. It is safe in pregnancy. It causes no harm to an unborn baby. If you become pregnant while using it, do not stop it using it without your doctor’s advice.

Low level of thyroid hormone could harm both mother and baby. Your doctor may increase your dose of levothyroxine during pregnancy.

Breastfeeding: 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.

Certain medicine may reduce levothyroxine effects, avoid taking them 4 hours before and 4 hours after taking levothyroxine.

  • Calcium carbonate
  • Ferrous sulfate iron supplement
  • Sucralfate
  • Cholestyramine, Colestipol
  • Sodium polystyrene sulfonate (Kalexate, Kayexalate, Kionex)
  • Antacids that contain aluminum or magnesium: Acid Gone, Gaviscon, Maalox, Milk of Magnesia, Mintox, Mylanta, Pepcid Complete, and others)

Avoid foods such as infant soy milk, cotton seed meal, walnuts, food high in fiber.
Several other conditions may reduce its effectiveness.

Make sure you inform your doctor of condition 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 or heavy feeling, 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 Levothyroid properly, you must follow all instructions given by your doctor.

Take Levothyroxine as prescribed by your doctor. You need to take it throughout your life. Check with your doctor, he may want to alter dose to get best possible effects.

It works best if you take it on an empty stomach. Try to take it 30 minutes before breakfast. Levothyroxine should be taken with a full glass, as it can dissolve very quickly and can swell in the throat, possibly causing choking or gagging.

Do not cut or crush the capsule. The whole capsule should be swallowed. If you are taking different strengths of levothyroxine, remove blisters from the capsule in advance it will help you in identifying the strengths of each capsule.

Infants or children may have difficulty in swallowing the whole capsule. Crush it and mix it with 1 or 2 teaspoonfuls of water. Use this mixture immediately. Do not store it for later use.

Dosage: Drug dose is different for different people based on body weight. You should follow your doctor’s direction. The following information is an average dose of this drug.

Oral dosage forms for tablet and capsules both.

For Hypothyroidism:

  • Adults: The usual dose is 1.7 microgram (mcg) per kilogram (kg) per day but may be less in older adults.
  • Children older than 12 years of age: The usual dose is 2 to 3 mcg per kg per day.
  • Children 6 to 12 years of age: The usual dose is 4 to 5 mcg per kg per day.
  • Children 1 to 5 years of age: The usual dose is 5 to 6 mcg per kg per day Dose is based on body weight and must be determined by your doctor.
  • Children 6 to 12 months of age: The usual dose is 6 to 8 mcg per kg per day.
  • Children 3 to 6 months of age: The usual dose is 8 to 10 mcg per kg per day.
  • Children 0 to 3 months of age: The usual dose is 10 to 15 mcg per kg per day.

For Thyroid Cancer:

  • Adults: The usual dose is more than 2 microgram (mcg) per kilogram (kg) per day.
  • Children: Use and dose must be determined by your doctor.

Missed Dose: If you miss a dose, take it as soon as you remember it. If it is almost the time for your next dose, skip the missed dose and go back to your regular schedule. Do not double the dose.

Storage: Store it at room temperature. Keep it away from children.

4 Precautions to Take

Before using Levothyroid, 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.

Levothyroxine can only treat infertility which is caused by hypothyroidism. It may alter blood sugar levels in the diabetic patient. Keep a track on your sugar levels. Go to your doctor if you notice any changes in your sugar levels.

If taken in large doses it may cause rapid or irregular heartbeats, chest pain, shortness of breath, leg cramps, headaches, nervousness, irritability, sleeplessness, tremors, a change in appetite, weight gain or loss, vomiting, diarrhea, excessive sweating, heat intolerance, a fever, changes in menstrual periods, hives, or a skin rash.

Go to your doctor immediately if you experience any of these symptoms.

Inform your doctor or dentist that you are using levothyroxine before any medical or surgical procedure. The doctor may want to stop this drug several days before surgery.

5 Potential Side Effects

As with many medications, there are several potential side effects associated with Levothyroid.

Consult with your doctor if they become problematic or frequent. Common side effects are mild hair loss.

Call your doctor at once if you have a serious side effect such as:

  • Fast or irregular heart rate.
  • Fever, hot flashes, sweating.
  • Sleep problems (insomnia).
  • Changes in your menstrual periods.
  • Vomiting, diarrhea, appetite changes, weight changes.

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.