Synthroid (Levothyroxine)

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What is Synthroid (Levothyroxine) prescribed for?

Synthroid (Levothyroxine) is used to treat hypothyroidism (underactive thyroid). The thyroid gland normally produces thyroid hormone, which is replaced or provided by this medication. Radiation, medication, or surgery can damage the thyroid gland and reduce thyroid hormone levels. In order to maintain normal mental and physical function, thyroid hormone needs to be sufficient. Normal mental and physical development in children depends on thyroid hormone levels. Besides treating thyroid cancer, this medication is also used to treat other thyroid disorders. There are no clinical studies to support the use of this medication to treat infertility unless low thyroid hormone levels are to blame.

Synthroid (Levothyroxine) FAQs

How To Use Synthroid?

The medication should be taken by mouth as directed by your doctor, usually 30 minutes or an hour before breakfast on an empty stomach. It is recommended that you take this medication with a full glass of water unless otherwise directed by your doctor.

Be sure not to split, crush, or chew this medication if you are taking it as a capsule. Infants and small children who cannot swallow capsules whole should take the medication as a tablet.

Crush the tablet and add 1 to 2 teaspoons (5-10 milliliters) of water. Give immediately with a spoon or dropper if an infant or child cannot swallow whole tablets. Ensure that a supply of tablets is not prepared in advance or mixed with soy infant formula. For more information, contact your pharmacist.

Your dosage is determined by your age, weight, weight loss or gain, medical condition, laboratory test results, and response to treatment. If you use any prescription, nonprescription, or herbal products, tell your doctor and pharmacist about them.

It is important to take this medication regularly for the maximum benefit. Make sure you take it at the same time every day, as this will make it easier for you to remember when to take it.

Thyroid replacement therapy is usually a lifelong treatment, so do not stop taking it without first consulting your doctor.

Levothyroxine is available in different brands. You should not change brands without first consulting your physician or pharmacist.

Tell your doctor if your condition gets worse or lasts after taking this medication for several weeks. Other symptoms include tiredness, muscle aches, constipation, dry skin, weight gain, and sensitivity to cold.

Store at room temperature when not in use, away from children and animals, when not in use.

What are the possible side effects of Synthroid?

The most commonly reported side effects of levothyroxine include:

  • fever
  • seizures
  • dilated neck veins
  • menstrual changes
  • decreased urine output
  • lack or slowing of normal growth in children
  • extreme fatigue
  • fainting
  • irregular breathing
  • hives or welts, skin itching, rash, or redness
  • sweating
  • pain or discomfort in the arms, jaw, back, or neck
  • swelling of the eyes, face, lips, throat, or tongue
  • heat intolerance
  • severe headache
  • blurred or double vision
  • dizziness
  • hair loss
  • irregular heartbeat

There are other side effects that may occur that are not listed on this page.

Seek immediate medical attention if you experience an allergic reaction or severe adverse reactions such as trouble breathing or chest pain.

What are Drug Interactions of Synthroid?

Few known Drug Interactions of Synthroid are listed below:

  • Losartan
  • Atorvastatin
  • Prednisone
  • Lisinopril
  • Singulair (Montelukast)
  • Amlodipine
  • Lasix (Furosemide)
  • Xanax (Alprazolam)
  • Hydrochlorothiazide
  • Metformin
  • Trazodone
  • Vitamin C (Ascorbic Acid)
  • Omeprazole
  • Cymbalta (Duloxetine)
  • Tramadol
  • Vitamin D3 (Cholecalciferol)
  • Gabapentin
  • Vitamin B12 (Cyanocobalamin)
  • Aspirin
  • Lipitor (Atorvastatin)

A complete list of Synthroid Drug Interactions is not available on this page.

Consult your physician if you have any questions about this medicine's drug interactions.

How much does Synthroid cost in Canada?

Starting price of Synthroid 25mcg cost in Canada.
- 90 tabs - $30.45 USD ($0.34 per tabs)

Starting price of Synthroid is 50mcg in Canada.
- 90 tabs - $33.60 USD ($0.37 per tabs)

Starting price of Synthroid 75 mcg cost in Canada.
- 90 tabs - $27.30 USD ($0.30 per tabs)

Please scroll up and refer to the products area for Synthroid 25 mcg, 50mcg, 75mcg, 88mcg, 100mcg, 112mcg, 125mcg, 137mcg, 150mcg, 175mcg, 200mcg, 300 mcg costs in Canada.

Disclaimer: The information contained in this page is to provide basic information on this product and is not intended to substitute medical advice from a licensed doctor. Always make sure to consult with a doctor before ordering medication online from Canada. Do not avoid or delay seeing a healthcare provider based on what you read here.