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) Information
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.
What is the recommended starting dose of Synthroid?
The recommended starting dose of Synthroid (levothyroxine) varies based on the patient’s age, weight, medical condition, and reason for treatment. For healthy adults with hypothyroidism, the typical starting dose is 1.6 mcg per kg of body weight per day. Older adults or those with heart disease are usually prescribed a lower dose of 12.5 to 25 mcg per day to reduce the risk of heart complications.
For children, the dosage is determined based on age and weight as directed by a doctor. It is important to consult a healthcare provider to determine the appropriate dose.
Synthroid cost in Canada?
Starting price of Synthroid 25mcg in Canada
-25mcg - 90 tabs - $38.70 USD ($0.43 per tab)
-50mcg - 90 tabs - $40.85 USD ($0.45 per tab)
-75mcg - 90 tabs - $39.55 USD ($0.44 per tab)
Scroll up to see the specific pricing for each product, which is available in various strengths for both brand-name and generic options.
Synthroid (Levothyroxine) FAQs
Is Synthroid the same as Levothyroxine?
Synthroid and Levothyroxine have the same active ingredient and work the same way. The main difference is that Synthroid is a brand name, while Levothyroxine is the generic version.
How long does it take for Synthroid to start working?
Synthroid usually starts working within a few days, but it may take 4 to 6 weeks to feel the full effects.
Can Synthroid be used for weight loss?
Synthroid is not a weight loss medication. It is used to treat hypothyroidism. While it may help with weight loss if you have an underactive thyroid, taking it without a thyroid condition can be dangerous and is not recommended.
Can I take Synthroid at night instead of in the morning?
Yes, you can take Synthroid at night instead of in the morning, as long as you take it on an empty stomach and at the same time each day. Just make sure it’s at least 3 to 4 hours after your last meal for proper absorption.
What should I do if I have an allergic reaction to Synthroid?
If you have an allergic reaction to Synthroid, such as rash, swelling, trouble breathing, or severe dizziness, seek medical help immediately. Stop taking the medication and contact your doctor as soon as possible.
Can Synthroid cause diarrhea or constipation?
Yes, Synthroid can cause digestive issues like diarrhea or constipation, though these side effects are not very common. If they persist or become severe, talk to your doctor.