Synthroid Medication Information:

Price Break On Synthroid
Generic is available for less money: Generic Levoxyl

Synthroid medication comes in several different strengths; click on the strength you need to view prices from pharmacies competing to earn your business.

Synthroid 0.025 mg
Synthroid 0.050 mg
Synthroid 0.075 mg
Synthroid 0.088 mg
Synthroid 0.100 mg
Synthroid 0.112 mg
Synthroid 0.125 mg
Synthroid 0.137 mg
Synthroid 0.150 mg
Synthroid 0.175 mg
Synthroid 0.200 mg

Synthroid General Information

Synthroid is used to treat some thyroid problems. It is a hormone, a synthetic one. Generally, this type of hormone is naturally made by one's thyroid glands. This drug is also called Levothyroxine.

How does Synthroid work?

Synthroid is used to replace these hormones. Usually, when a person needs to be treated with replacement of thyroid hormones, they may have to get this treatment for the rest of their life. When a person has an underactive or an enlarged thyroid, the hormones stop producing as they should. This causes the hormones to go out of control, therefore causing someone's moods, energy, and metabolism to change. The Synthroid helps to regulate these changes by adding hormones back into the body and balancing the hormones out. This medication is not used with people who are overweight or that have other weight troubles.

When/How is Synthroid taken/used/applied?

Like all medications, Synthroid should be taken exactly the way it is prescribed by a person's doctor, and for the amount of time it states on the prescription. Some people may have to take this for long periods of time or for the rest of their life. Some may only have to take it for a short time.

When taking this medicine, it is vital that it be taken along with an 8 oz. glass of water. The reason the medicine is taken with water is because of the size of the pill and the way the pill is made. It can swell up while someone tries to swallow it. If it does swell up in the throat, a person could choke on it. The water will help the pill to smoothly go down without any tragedies occurring.

It is highly recommended that Synthroid be taken an hour before consumption of food. The usual time that this medicine is taken is in the morning. As with most medications, it is recommended to take it at the same time each day. It usually takes 3-4 weeks for someone to feel affects of this medication working for them.Your doctor will order routine blood work, at certain times, to check levels of this medicine, and to make sure your liver and kidneys are doing alright with the medicine.

Side Effects of Synthroid

Some of the mild side effects with Synthroid are things like a mild headache, edginess, a little trouble falling asleep, possible sweats or heat flashes, possible low grade fever, changes in the menstrual cycle, and changes in one's eating habits. Another mild side effect could be some hair loss, but this is rare.

Serious, but rare, side effects of Synthroid are things that could be considered an allergic reaction to this medicine. If these following side effects occur, seek medical help immediately. Some of these side effects are parts of the body swelling up; hands, feet, face, lips, or the tongue. Other serious side effects that can occur, and could be an allergic reaction are breaking out in hives or an itchy, thick rash or trouble with your breathing.

One other severe side effect that that could occur, but is rare, is seizures. If this were to occur, it usually occurs when a person just begins to take this medicine.

Other side effects could happen, but may not be listed here. All side effects that have been studied and tested are listed on the medicines paperwork.

Other Brand Names for Synthroid:

  • Synthroid
  • Unithroid
  • Levoxyl
  • Levothroid

Safety Information:

People who have been diagnosed with heart problems or who are anemic, diabetic, or who have been diagnosed with a pertinent medical condition should always tell their doctor about any pre-existing conditions before taking Synthroid.

Diabetics who depend on insulin or who take other diabetes medications may need to change the dose of their diabetic medicine when they take Synthroid.

Each person may be different with this medicine, so each person may have to take a different brand of Synthroid. Make sure that the pills you get with your prescription are the right ones, as there are a few different brands of Synthroid.

Thyrotoxicosis is another thyroid problem some people get diagnosed with. These people should not take Synthroid.

Some people who have pituitary or adrenal gland diagnoses should not take this medication.

Always tell your physician about any medications you have been taking, including any form of vitamins. Some medication can counteract with one another and can sometimes cause serious problems. Your doctor will have a list of all medicines that should not be taken at the same time as Synthroid. Also, while you are taking Synthroid, if you are prescribed something new to take, or wish to try a new vitamin or natural herb, ask your physician about it first.

It has been known that this medicine can cause bone problems, like Osteoporosis, if taking for a long period of time; like several years.

If a woman is pregnant, planning on having a little one, or is breastfeeding an infant, they should be able to take this medicine. The medicine has been proven to be safe for women in this category in life. You and your physician can decide the best about this.

Foods like walnuts, soy milk, meal with cotton seed, and food that are rich in fiber should be avoided while taking Synthroid. These foods can lessen the positive effects of the medicine.



  • 25 mcg
  • 50 mcg
  • 75 mcg
  • 88 mcg
  • 100 mcg
  • 112 mcg
  • 125 mcg
  • 137 mcg
  • 150 mcg
  • 175 mcg
  • 200 mcg
  • 300 mcg

Mcg = micrograms = 1/1000 of a milligram (mg)

Visual Description:

  • 25 mcg - This tablet is light peachy-pink, with 25 written on it.
  • 50 mcg - This tablet is white, with 50 written on it.
  • 75 mcg - This tablet is light bluish purple and has 75 written on it.
  • 88 mcg - This tablet is light green and has 88 written on it.
  • 100 mcg - This tablet is medium yellow and has 100 written on it.
  • 112 mcg - This tablet is medium pink and has 112 written on it.
  • 125 mcg - This tablet is grayish white and has 125 written on it.
  • 137 mcg - This tablet is a bit darker than the color turquoise and has 137 written on it.
  • 150 mcg - This tablet is medium blue and has 150 written on it.
  • 175 mcg - This tablet is purple and has 175 written on it.
  • 200 mcg - This tablet is light pink and has 200 written on it.
  • 300 mcg - This tablet is light blue and has 300 written on it.

Each tablet also has a little indent on two side of the face edge of it. It looks like they began to cut them in half, but they only did two of the edges and not across the center.

About Synthroid

What Synthroid is used for

SYNTHROID is used when the thyroid gland does not produce enough hormone (hypothyroidism). It is also used to help decrease the size of enlarged thyroid glands (known as goiter) and to treat thyroid cancer.

What Synthroid does

SYNTHROID contains levothyroxine sodium, the same as the thyroxine hormone, produced by the normally functioning thyroid gland.

The thyroid gland produces and releases two hormones: thyroxine and liothyronine. In other areas of the body, thyroxine is changed into liothyronine, which is a more active form of thyroid hormone. These hormones are responsible for maintaining a normal rate of metabolism in the body.

When the thyroid gland is unable to produce normal amounts of thyroxine, the level of thyroid hormones in the blood decreases (hypothyroidism). This results in a reduced rate of metabolism.

Levothyroxine sodium in SYNTHROID is intended to replace a hormone that is normally produced by your thyroid gland. Generally, replacement therapy is to be taken for life, except in cases of transient (temporary) hypothyroidism, which is usually associated with an inflammation of the thyroid gland (thyroiditis). Low levels of thyroid hormone interfere with the proper function of many organs and affect metabolism.

When Synthroid should not be used

SYNTHROID should not be used in patients with:

  • Any unusual or allergic reaction to thyroid hormones or any of the inactive ingredients.

  • Over active thyroid gland (thyrotoxicosis) of any cause.

  • Uncorrected adrenal gland under-activity.

What the medicinal ingredient is

Levothyroxine sodium, USP.

What the important nonmedicinal ingredients for Synthroid are

Acacia, confectioner's sugar, lactose, magnesium stearate, povidone, talc and colour additives.

What dosage forms Synthroid comes in

SYNTHROID comes as tablets in the following strengths: 25 µg, 50 µg, 75 µg, 88 µg, 100 µg, 112 µg, 125 µg, 137 µg, 150 µg, 175 µg, 200 µg and 300 µg.

Warnings and Precautions

Serious Warnings and Precautions

Thyroid hormones, including SYNTHROID, either alone or with other medicines, should not be used for the treatment of obesity or for weight loss as they could produce serious or even life threatening side effects.

BEFORE or WHILE you use SYNTHROID tell your doctor or pharmacist if:

  • You are allergic to any foods or medication.

  • You are pregnant or intend to become pregnant, or are breast-feeding. If you become pregnant while taking SYNTHROID, your dose of SYNTHROID will likely have to be increased.

  • You have any heart problem, whether or not you have received treatment for them (especially history of heart attack, heart disease, hardening of the arteries).

  • You have other medical problems, whether or not you have received treatment for them (especially high blood pressure, osteoporosis, blood clotting disorder, or history of thyroid, adrenal and/or pituitary gland problems).

  • You have diabetes. Your dose of insulin or oral antidiabetic agent may need to be changed after starting SYNTHROID. You should monitor your blood and urinary sugar levels as directed by your doctor and report any changes to your doctor immediately.

  • You are taking an oral anticoagulant (blood thinner) such as warfarin. Your dose may need to be changed after starting SYNTHROID.

  • You are taking any other medications (prescription or over-the-counter).

  • You are planning to have any kind of surgery (including dental surgery) or emergency treatment. You should inform your doctor or dentist that you are taking SYNTHROID before having any kind of surgery.

  • Your brand of levothyroxin was changed.

  • You are a woman on long-term therapy. You may experience decrease in bone density.

  • You have any allergies to this drug or its ingredients or components of the container.

Interactions with Synthroid

Drugs that may interact with SYNTHROID include but are not limited to the following:

  • Digitalis glycosides (e.g. digoxin)

  • Anti-diabetic agents (insulin or oral hypoglycaemic drugs)

  • Glucocorticoids (corticosteroids such as dexamethasone or prednisone)

  • Antacids containing aluminium and magnesium (e.g. Aluminium and magnesium hydroxides, simethicone)

  • Calcium carbonate

  • Diazepam (e.g. Valium)

  • Ferrous sulphate

  • Antidepressants

  • Lithium

  • Iodide

  • Anticoagulants (blood thinners)

  • Appetite suppressants (diet pills)

  • Beta-blockers

  • Cholestyramine (e.g., Questran)

  • Colestipol (e.g., Colestid)

  • Medicines for asthma or other breathing problems

  • Medicines for colds, sinus problems, hay fever or other allergies (including nose drops or sprays)

Some medicines may interfere with any blood tests done to determine thyroid hormone levels (thyroid function tests). It is important to inform your doctor of all medicines you are taking before and at the time of blood tests.

Eating certain foods such as soybean flour, soybean infant formula, cotton seed, walnuts and dietary fiber may decrease absorption of levothyroxine. You may require a change in the dose.

Proper Use of Synthroid

Use SYNTHROID only as prescribed by your doctor. Thyroid hormone replacement is usually taken for life. Do not change the amount you take or how often you take it, unless directed to do so by your doctor. Like all medicines obtained from your doctor, SYNTHROID must be used only by you and for the condition determined appropriate by your doctor. Do not stop taking levothyroxine sodium without talking to your doctor.

Take SYNTHROID as a single dose, preferably on an empty stomach, one half-to one hour before breakfast. SYNTHROID should be taken with a full glass of water. As food and drink can significantly change the absorption of SYNTHROID, you are advised to take SYNTHROID at the same time every day and be consistent in how you take it with regards to meals [i.e. either always take it on an empty stomach (preferred method) or always take it with food]. Levothyroxine sodium absorption is increased on an empty stomach.

Usual dose

The dose of these medicines will be different for different patients. Follow your doctor's orders or the directions on the label.

Treatment is usually started with lower doses that are increased a little at a time to prevent side effects.

Adults and children (>12): Therapy is usually initiated at the anticipated full replacement dose. The dosage is adjusted by 12.5 to 25 µg increments.

Patients older than 50 years or patients younger than 50 years with a history of cardiovascular disease: The starting dose should be 25 to 50 µg once daily with adjustments every 6 to 8 weeks as needed.

Elderly patients with cardiac disease: The recommended starting dose is 12.5 to 25 µg/day, with gradual dose increments at 4 to 6 week intervals.


If you or someone you know accidentally takes more than the prescribed dose, contact your doctor immediately or go to the nearest hospital with the tablets. Tell your doctor or hospital how much was taken. Treat even small overdoses seriously.

Missed dose

If you forget to take one tablet, take another as soon as you remember, unless it is almost time for your next dose. If it is, take the dose you missed with your next dose.

If you miss 2 or more doses in a row or if you have any questions about this, check with your doctor.

Side Effects for Synthroid and What to Do About Them

Side effects with SYNTHROID are rare and usually related to overdosing. They include:

  • Chest pain

  • Fast or irregular heart beat

  • Weight loss or gain

  • Sweating

  • Nervousness

  • Temporary hair loss

  • Decrease of bone mineral density

  • Diarrhea

  • Vomiting

Synthroid Facts

New drugs laws resulted in application for reapproval of Synthroid by the FDA, which was granted in 2002.

Synthroid is a synthetic form of thyroxine (T4), which is one of two primary hormones produced by the thyroid.

Synthroid became available as a generic called levothyroxine in 2004.

Synthroid was the second most often prescribed medication in the U.S. in 2002.


Technical Information