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Unithroid (Oral)

Generic name: levothyroxinelee-voe-thye-ROX-een ]
Brand names: Ermeza, Levothroid, Levoxyl, Synthroid, Tirosint, Tirosint-Sol, Unithroid
Drug class: Thyroid drugs

Medically reviewed by Drugs.com. Last updated on Dec 12, 2023.

Oral route(Capsule;Tablet;Solution)

Thyroid hormones, including levothyroxine, should not be used either alone or with other therapeutic agents for the treatment of obesity or weight loss. In euthyroid patients, doses within the range of daily hormonal requirements are ineffective for weight reduction. Larger doses may produce serious or even life-threatening manifestations of toxicity, particularly when given in association with sympathomimetic amines such as those used for their anorectic effects .

Uses for Unithroid

Levothyroxine is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. Levothyroxine is also used to help decrease the size of enlarged thyroid glands (also called a goiter) and to treat thyroid cancer.

This medicine is available only with your doctor's prescription.

Before using Unithroid

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For this medicine, the following should be considered:

Allergies

Tell your doctor if you have ever had any unusual or allergic reaction to this medicine or any other medicines. Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals. For non-prescription products, read the label or package ingredients carefully.

Pediatric

Appropriate studies performed to date have not demonstrated pediatric-specific problems that would limit the usefulness of levothyroxine in children. However, your child's doctor will check your child closely for heart problems during the first 2 weeks of treatment.

Geriatric

Appropriate studies performed to date have not demonstrated geriatric-specific problems that would limit the usefulness of levothyroxine in the elderly. However, elderly patients are more likely to have age-related heart or blood vessel problems, which may require caution and an adjustment in the dose for patients receiving levothyroxine.

Breast Feeding

Studies in women suggest that this medication poses minimal risk to the infant when used during breastfeeding.

Interactions with Medicines

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking this medicine, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

Interactions with Food/Tobacco/Alcohol

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.

Using this medicine with any of the following may cause an increased risk of certain side effects but may be unavoidable in some cases. If used together, your doctor may change the dose or how often you use this medicine, or give you special instructions about the use of food, alcohol, or tobacco.

Other Medical Problems

The presence of other medical problems may affect the use of this medicine. Make sure you tell your doctor if you have any other medical problems, especially:

Proper use of Unithroid

This medicine will need to be taken for the rest of your life or your child's life. Do not stop taking this medicine or change your dose without first checking with your doctor. You may have to take this medicine for 4 to 8 weeks before your symptoms start to get better.

Take this medicine in the morning on an empty stomach, at least 30 to 60 minutes before eating breakfast.

Swallow the capsule whole. Do not cut, chew, or crush it.

If your child is unable to swallow the tablet, you may crush and mix it in 1 to 2 teaspoons (5 to 10 milliliters) of water. Give the mixture right away using a spoon or dropper. Do not mix the tablet with any other liquid except water. Do not store the mixture for future use.

If you are using the oral liquid:

If you are using kayexalate, lanthanum, orlistat, sevelamer, sucralfate, antacids (eg, aluminum or magnesium hydroxide, simethicone, Maalox®, Mylanta®, Tums®), medicine to lower cholesterol (eg, cholestyramine, colesevelam, colestipol, Prevalite®,Welchol®, Colestid®), stomach medicine (eg, lansoprazole, omeprazole, pantoprazole, Aciphex®, Dexilant®, Nexium®, Prevacid®, Prilosec®), or any medicine that contains calcium or iron, take them at least 4 hours before or 4 hours after you take levothyroxine.

Cotton seed meal, dietary fiber, soybean flour (infant formula), or walnuts may decrease the absorption of this medicine from your body. You may have to take this medicine at a different time of day from when you eat these foods. Talk with your doctor more about this if you have concerns.

Do not eat grapefruit or drink grapefruit juice while you are using this medicine.

Dosing

The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

Missed Dose

If you miss a dose of this medicine, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not double doses.

Storage

Keep out of the reach of children.

Do not keep outdated medicine or medicine no longer needed.

Ask your healthcare professional how you should dispose of any medicine you do not use.

Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light. Keep from freezing.

Use the oral liquid within 15 days after opening the pouch. Keep the ampules in the pouch until you are ready to use them.

Precautions while using Unithroid

It is very important that your doctor check the progress of you or your child at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests will be needed to check for unwanted effects.

Levothyroxine should not be used for the treatment of obesity or for the purpose of losing weight. This medicine is not effective for weight reduction. If taken in large amounts, levothyroxine may cause serious unwanted effects.

Hypothyroidism can sometimes cause infertility in men and women. Levothyroxine should not be used for the treatment of infertility unless it is caused by hypothyroidism.

For patients with diabetes: It is very important that you keep track of your blood or urine sugar levels as instructed by your doctor. Check with your doctor right away if you notice any changes in your sugar levels.

If you think you have become pregnant while using this medicine, tell your doctor right away. You may need a larger dose of levothyroxine while you are pregnant.

Women who are post-menopausal or who use this medicine for a long time may have some bone loss, which could lead to osteoporosis. Talk with your doctor if you have questions or concerns about this.

Call your doctor right away if you or your child has rapid or irregular heartbeats, chest pain, 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. These could be symptoms of too much medicine in your body.

This medicine may cause severe hypothyroidism, called myxedema coma, which may be life-threatening and requires immediate medical attention. Check with your doctor right away if you have weakness, confusion or non-responsiveness, feeling cold, low body temperature, swelling of the body, especially the face, tongue, and lower legs, or difficulty breathing.

Do not suddenly stop taking this medicine without first checking with your doctor. Your doctor may want you or your child to gradually reduce the amount you are using before stopping completely.

Make sure any doctor or dentist who treats you knows that you or your child are using this medicine. You or your child may need to stop using this medicine several days before having surgery or medical tests.

A temporary loss of hair may occur during the first few months of levothyroxine therapy. Ask your doctor about this if you have any concerns.

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

Side Effects of Unithroid

Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur:

Less common

Rare

Get emergency help immediately if any of the following symptoms of overdose occur:

Symptoms of overdose

Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.

Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Commonly used brand name(s)

In the U.S.

Available Dosage Forms:

Therapeutic Class: Thyroid Supplement

Frequently asked questions

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.