Unithroid is a brand-name oral tablet that’s prescribed for certain thyroid conditions. Unithroid contains the active drug levothyroxine and belongs to the thyroid hormone drug class.
Unithroid is FDA-approved to:
- treat hypothyroidism in people of all ages
- suppress (lower) thyroid-stimulating hormone levels in people of all ages with a certain type of thyroid cancer
You’ll find key information about Unithroid below:
- Drug form: oral tablet
- Generic available? Yes
- Prescription required? Yes
- Controlled substance? No
- Year of FDA approval: 2001
Unithroid is a brand-name medication that contains the active drug levothyroxine. This drug is also available as a generic medication. A generic drug is an exact copy of the active drug in a brand-name medication.
The generic version is considered to be as safe and effective as the original drug. Generics tend to cost less than brand-name drugs.
If you’re interested in the generic form of Unithroid, talk with your doctor. They can tell you whether it comes in forms and strengths that can be used for your condition.
Unithroid can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Unithroid. These lists do not include all possible side effects.
For more information about the possible side effects of Unithroid, talk with your doctor or pharmacist. They can give you tips on how to manage any side effects that may be concerning or bothersome.
Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to notify the FDA about a side effect you’ve had with Unithroid, you can do so through MedWatch.
Mild side effects
Below is a partial list of mild side effects of Unithroid. To learn about other mild side effects, talk with your doctor or pharmacist, or view Unithroid’s prescribing information.
Mild side effects of Unithroid can include:
- weight loss
- increased appetite, which may lead to weight gain
- nervousness or irritability
- muscle tremors, spasms, or weakness
- shortness of breath
- heat sensitivity
- irregular periods
- skin rash
- hair loss
- mild allergic reaction*
Most of these side effects may go away within a few days to a couple of weeks. However, if they become more severe or don’t go away, talk with your doctor or pharmacist.
* For more information about allergic reaction and Unithroid, see “Allergic reaction” below.
Serious side effects
Serious side effects from Unithroid aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.
Serious side effects and their symptoms can include:
- Low bone density. Symptoms can include:
- bones that break easily
- bone pain
- loss of height
- Heart problems, such as heart attack or irregular heart rate. Symptoms can include:
- pressure, tightness, or pain in the chest
- pain in the jaw, neck, back, or arms
- shortness of breath
- Severe allergic reaction.*
* For details about allergic reaction and Unithroid, see “Allergic reaction” below.
Side effects in children
Most side effects of Unithroid are similar in children and adults. See the “Mild side effects” and “Serious side effects” lists above for examples.
- pseudotumor cerebri (increased pressure around the brain)
- slipped capital femoral epiphysis (a hip condition)
- craniosynostosis (a skull condition)
- bone growth problems, which can lead to decreased height
If you’re concerned about the side effects of Unithroid in children, talk with your child’s doctor or pharmacist.
Symptoms of a mild allergic reaction can include:
A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include:
- swelling under your skin, typically in your eyelids, lips, hands, or feet
- swelling of your tongue, mouth, or throat
- trouble breathing
Call your doctor right away if you have an allergic reaction to Unithroid, as the reaction could become severe. Call 911 or your local emergency number if your symptoms feel life threatening or if you think you’re having a medical emergency.
Other drugs are available that can treat your condition. Some may be a better fit for you than others. If you’re interested in finding an alternative to Unithroid, talk with your doctor. They can tell you about other medications that may work well for you.
The following drugs are similar to Unithroid:
The Unithroid dosage your doctor prescribes will depend on several factors. These include:
- the type and severity of the condition you’re taking Unithroid to treat
- your age
- your body weight in kilograms*
- other medical conditions you may have
- other medications you’re taking
The following information describes dosages that are commonly prescribed or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.
* For reference, 1 kilogram (kg) is about 2.2 pounds (lb).
Drug forms and strengths
Unithroid comes as an oral tablet. It’s available in the following strengths:
- 25 micrograms (mcg)
- 50 mcg
- 75 mcg
- 88 mcg
- 100 mcg
- 112 mcg
- 125 mcg
- 137 mcg
- 150 mcg
- 175 mcg
- 200 mcg
- 300 mcg
Dosage for hypothyroidism
Unithroid is approved to treat hypothyroidism. Typically, your doctor will prescribe a low dosage to start. They may refer to this as your starting dosage.
For this use, the recommended starting dosage of Unithroid is 1.6 mcg per kilogram (mcg/kg) of body weight once per day. For example, if you weigh 70 kg (about 154 lb), your starting dosage will be 112 mcg of the drug once per day. Your doctor will calculate your dosage. They may adjust your dosage over time until your thyroid hormone levels reach the desired range.
Your doctor may prescribe a different starting dosage in certain situations, such as pregnancy. If you have questions about the dosage that’s right for you, talk with your doctor.
Dosage for TSH suppression
For this use, your Unithroid dosage depends on your treatment plan. Your doctor will prescribe a Unithroid dosage that results in the desired TSH level. Always take the dosage your doctor prescribes for you.
Unithroid is prescribed to treat hypothyroidism and suppress TSH in children of all ages. Keep reading to learn about children’s dosages for each use.
Children’s dosage for hypothyroidism
Children’s dosages for hypothyroidism depend on their age and body weight. The table below shows typical dosages for children:
|Child’s age||Recommended dosage|
|under 3 months||10–15 mcg/kg once per day|
|3 months to under 6 months||8–10 mcg/kg once per day|
|6 months to under 1 year||6–8 mcg/kg once per day|
|1–5 years||5–6 mcg/kg once per day|
|6–12 years||4–5 mcg/kg once per day|
|over 12 years but before puberty and still growing||2–3 mcg/kg once per day|
|over 12 years but after puberty and done growing||1.6 mcg/kg once per day|
For example, if your child is 4 years old, their doctor may prescribe 5 mcg/kg of Unithroid once per day. If your child weighs 15 kg (about 33 lb), their dosage would be 75 mcg of the drug once per day. Your child’s doctor will calculate their dosage. They may adjust it over time until your child’s thyroid hormone levels reach the desired range.
Your child’s doctor may prescribe a different dosage depending on certain factors. These include your child’s risk of heart failure and the presence of hyperactive behavior. If you have questions about the dosage that’s right for your child, talk with their doctor for more information.
Children’s dosage for TSH suppression
For TSH suppression, your child’s Unithroid dosage depends on their treatment plan. Your child’s doctor will determine the right dosage to reach the desired TSH level.
About taking Unithroid
Below you’ll find information about key dosage issues:
- When to take: You should take Unithroid once daily on an empty stomach, usually 30–60 minutes before your first meal of the day. Taking the medication at around the same time of day helps keep a steady level of the drug in your body. This helps Unithroid work effectively.
- If you miss a dose: If you miss a dose, talk with your doctor or pharmacist. They can recommend the best time for you to take the next dose of the drug.
- Taking Unithroid with food: You should avoid eating food at least 30 minutes to 1 hour after taking Unithroid. This is because taking Unithroid with food lowers the level of the drug in your body. And this may make it less effective.
- Crushing, splitting, or chewing Unithroid: The drug’s manufacturer hasn’t stated whether the tablets can be split or chewed. However, if you or a child has trouble swallowing the tablets whole, you can crush them: Mix the crushed tablets with 1–2 teaspoons of water and drink the mixture right away. You can also see suggestions for swallowing tablets in this article, or talk with your doctor or pharmacist.
- Length of use: Unithroid is meant to be a long-term treatment. If you and your doctor determine that Unithroid is safe and effective for you, you’ll likely take it long term.
Taking more than the recommended dosage of Unithroid can lead to harmful effects. Do not take more Unithroid than your doctor recommends. To learn about side effects of Unithroid, see the “Unithroid side effects” section above.
Symptoms of an overdose can include:
What to do in case of overdose
If you think you’ve taken too much of this drug, call your doctor. You can also call America’s Poison Centers at 800-222-1222 or use its online tool. However, if your symptoms are severe, call 911 or your local emergency number, or go to the nearest emergency room right away.
As with all medications, the cost of Unithroid can vary. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.
Drug coupons: You can visit Optum Perks* for price estimates of Unithroid. These estimates are based on the use of Optum Perks coupons. Note: Optum Perks coupons cannot be used with any insurance copays or benefits.
Financial and insurance assistance: If you need financial support to pay for Unithroid, or if you need help understanding your insurance coverage, help is available.
To learn more about saving money on prescriptions, check out this article.
Generic version: Unithroid is available in a generic version called levothyroxine. A generic drug is an exact copy of the active drug in a brand-name medication. The generic is considered to be as safe and effective as the original drug. And generics tend to cost less than brand-name drugs. To find out how the cost of levothyroxine compares with the cost of Unithroid, talk with your doctor or pharmacist.
* Optum Perks is a sister site of Medical News Today.
Here are answers to some frequently asked questions about Unithroid.
Is Unithroid gluten free?
Yes, according to the drug’s manufacturer, Unithroid is gluten free.
Some drugs have inactive ingredients made from grains that contain gluten. These grains may include rye, wheat, or barley. However, Unithroid doesn’t contain any ingredients made from these grains.
If you have questions about this, talk with your doctor or pharmacist for more information.
Does Unithroid cause long-term side effects?
Yes, in some cases, Unithroid may cause long-term side effects. These can occur during treatment and last for a while after you no longer take the drug.
If you have questions about long-term side effects from Unithroid, talk with your doctor or pharmacist. They can discuss your risk of long-term side effects and how to manage them if they occur.
How does Unithroid work?
Unithroid treatment increases your thyroid hormone to a level that’s within a normal range. As a result, Unithroid helps ease symptoms of hypothyroidism.
Unithroid also suppresses (lowers) thyroid-stimulating hormone (TSH) levels. This is important for people who’ve received thyroid cancer treatment.
Usually, low T4 levels due to thyroid cancer surgery or radioactive iodine treatment signal your body to make TSH. However, TSH helps your thyroid gland grow more cells, which may include thyroid cancer cells. With Unithroid treatment, your thyroid hormone level will be within a normal range. So your body won’t make TSH. This lowers your TSH, which helps prevent thyroid cancer cells from growing.
If you have questions about what to expect with Unithroid treatment, talk with your doctor. To learn more about the conditions Unithroid treats, see the “Unithroid uses” section below.
Unithroid can interact with several other medications. It can also interact with certain supplements as well as certain foods.
Before taking Unithroid, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.
Interactions with medications, foods, and supplements
Below is a list of medications, supplements, and foods that can interact with Unithroid. This list does not contain all drugs that may interact with Unithroid. If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.
|Medications that can interact with Unithroid||• certain birth control pills, such as ethinyl estradiol/norgestimate (Estarylla, Sprintec, others) and ethinyl estradiol/norethindrone (Aranelle, Gildagia, others)|
• proton pump inhibitors such as esomeprazole (Nexium) and lansoprazole (Prevacid)
• antacids such as calcium carbonate (TUMS) and aluminum hydroxide/magnesium hydroxide (Maalox)
• diabetes drugs such as metformin (Fortamet, Glumetza) and glimepiride (Amaryl)
• corticosteroids such as prednisone (Rayos) and dexamethasone (Hemady)
• beta-blockers such as atenolol (Tenormin) and propranolol (Inderal LA, InnoPran XL)
• tricyclic antidepressants such as amitriptyline and imipramine (Tofranil)
• certain blood thinners such as heparin and warfarin (Jantoven)
• digoxin (Lanoxin)
• furosemide (Lasix)
|Vitamins or supplements that can interact with Unithroid||• calcium supplements|
• iron supplements
• multivitamins that contain calcium or iron
|Foods that can interact with Unithroid||• soy-based flour, including soy infant formula|
• cottonseed flour
• high fiber foods such as black beans and sweet potatoes
Alcohol isn’t known to interact with Unithroid. It’s likely safe to consume alcohol while taking Unithroid.
If you have questions about the safety of drinking alcohol while taking Unithroid, talk with your doctor or pharmacist.
The Food and Drug Administration (FDA) approves prescription drugs such as Unithroid to treat certain conditions. Unithroid may also be used off-label for other conditions. Off-label drug use is when an FDA-approved drug is prescribed for a purpose other than what it’s approved for.
Unithroid for hypothyroidism
Unithroid is approved to treat hypothyroidism in adults and children of any age.
Doctors may prescribe Unithroid for different types of hypothyroidism, including:
- primary hypothyroidism, which can happen with thyroid gland damage
- pituitary (secondary) hypothyroidism, which happens when the pituitary gland* doesn’t function as usual
- tertiary hypothyroidism, which happens when the hypothalamus (a small structure in the brain) doesn’t function as usual
Doctors typically won’t prescribe Unithroid for hypothyroidism in a person recovering from subacute thyroiditis (a rare type of thyroid inflammation).
* The pituitary gland is part of your endocrine system. It’s just below the brain and secretes hormones with many functions.
Unithroid for TSH suppression
With thyroid cancer, cancer cells begin growing in the thyroid gland but may spread to other areas of the body. Symptoms can include nodules (lumps in the thyroid gland near the front of your throat). Swelling or pain in your neck is also possible.
For this purpose, Unithroid is typically prescribed after certain other treatments for thyroid cancer. These include surgery to remove the thyroid gland and radioactive iodine treatments.
Doctors typically will not prescribe Unithroid for TSH suppression in a person with certain conditions. These include certain goiters (enlarged thyroid gland) and noncancerous thyroid nodules.
To learn more, see “How does Unithroid work?” in the “Common questions about Unithroid” section above.
Unithroid and children
Unithroid is approved to treat hypothyroidism and suppress TSH levels in children of all ages.
To learn more about these conditions, see the “Unithroid for hypothyroidism” and “Unithroid for TSH suppression” sections above. You can also talk with your child’s doctor.
If you can become pregnant, consider the following information about pregnancy, birth control, and breastfeeding.
Unithroid and pregnancy
In general, Unithroid is considered safe to take during pregnancy. However, you should still ask your doctor whether they feel it’s safe for you.
Unithroid and birth control
Unithroid is generally considered safe to take during pregnancy. Still, if you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re taking Unithroid.
Keep in mind that Unithroid may interact with certain birth control pills. (For examples, see the “Unithroid interactions” section above.) Your doctor can recommend what to do if you take birth control pills that interact with Unithroid. They can also recommend birth control options that don’t interact with this drug.
Unithroid and breastfeeding
It’s not known whether Unithroid should be taken while breastfeeding. If you’re currently breastfeeding or planning to do so, talk with your doctor before taking this medication.
This drug comes with several precautions.
FDA warning: Not for use to treat obesity or as a weight loss aid
This drug has a
Not for use to treat obesity or as a weight loss aid. Unithroid is not approved by the FDA to treat obesity or for use as a weight loss aid. Taking the drug for these purposes could lead to harmful effects, some of which may be life threatening. Examples include seizures and a blood clot in the brain.
Due to this risk, doctors will not prescribe Unithroid to treat obesity or as a weight loss aid. If you’re interested in treatment options for obesity or weight loss, talk with your doctor. They’ll recommend options for you.
Before taking Unithroid, discuss your health history with your doctor. Unithroid may not be right for you if you have certain medical conditions or other factors affecting your health. Be sure to talk with your doctor if any of the following apply to you:
- type 1 or type 2 diabetes
- adrenal insufficiency (a condition that occurs when the adrenal glands do not produce enough of certain hormones)
- myxedema coma (a severe form of hypothyroidism)
- cardiovascular disease
- being postmenopausal
- previous allergic reaction to this or a similar drug
- pregnancy and breastfeeding (see the “Things to consider when taking Unithroid” section above)
Note: For more information about the potential negative effects of Unithroid, see the “Unithroid side effects” section above.
Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.