What does synthroid do

Healthcare Professionals. Log out. Elisa shares her journey, from getting diagnosed to starting—and continuing—treatment with Synthroid, and living with hypothyroidism. Find out what Elisa does to make sure she gets her Synthroid at the pharmacy. Hear from Elisa as she talks about the importance of taking Synthroid the right way, every day.

Elisa talks about how she takes an active role in her Synthroid treatment. Learn more about hypothyroidism, its causes, and risk factors from Dr.

Elliot Levy. If you have a heart condition, your doctor may start you on a low dose and monitor you more closely than usual. Adrenal gland problems. Treatment with Synthroid can lower levels of your adrenal hormones, such as cortisol.

People with adrenal gland problems, such as adrenal insufficiency , may be at a higher risk for this side effect. Be sure your doctor is aware of any adrenal gland problems you have before you start taking Synthroid. Synthroid may cause your blood sugar level to rise if you have diabetes and take certain medications for it.

This is because Synthroid may cause some diabetes medications to work less well than usual. Your doctor may monitor your blood sugar more closely than usual if you have diabetes and begin taking Synthroid. Allergic reaction. Talk with your doctor about which other treatments are better choices for you. Problems with blood clotting. Certain medications called blood thinners might work better than usual if used together with Synthroid.

But this can also lead to serious side effects, such as excessive bleeding. Your doctor may monitor you more closely than usual if you take Synthroid with a blood thinner. They may also lower the dose of your blood thinner. Being an older adult. So your doctor may start you on a low dose and monitor you more closely than usual.

Having gone through menopause. Synthroid may cause decreased bone mineral density BMD. They may monitor your BMD throughout your treatment. Your doctor may change your Synthroid dose based on your hormone levels. This helps them choose a Synthroid dose that works best for you. But if you become pregnant during your treatment, your doctor may need to increase your dose of Synthroid.

This is because pregnancy can sometimes increase the need for thyroid hormones. Keep in mind that untreated hypothyroidism can be dangerous during pregnancy. The drug is believed pass into human breast milk. Talk with your doctor about the risks and benefits of treatments for your condition while breastfeeding. Taking the drug exactly as prescribed by your doctor should lower your risk for side effects of Synthroid. In rare cases, Synthroid can cause serious side effects. You should talk with your doctor if you experience symptoms of:.

You should also talk with your doctor if you become pregnant while taking Synthroid. If you become pregnant, your doctor may need to increase your dose of the drug. They can help answer any questions you have about side effects of taking the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:. 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 other 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. Certain foods and supplements may improve or worsen symptoms of hypothyroidism, or an underactive thyroid.

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Hypothyroidism and depression can produce similar symptoms. For example, both can cause changes in mood. Learn about the links between them here. Hair loss sometimes occurs if the thyroid gland is not working correctly. An overactive thyroid or an underactive thyroid can both cause hair loss….

Cannabidiol CBD is a compound in the cannabis plant that may help ease cancer symptoms and side effects of treatment. This includes the medications:. These medications may decrease the amount of Synthroid in your body. And this interaction could make Synthroid less effective for you. If you do take simethicone or sucralfate with Synthroid, your doctor may order blood tests more often than usual to monitor your thyroid health. Some drugs used to treat depression may interact with Synthroid.

Certain antidepressants can lower the level of Synthroid in your body, while other antidepressants can raise the level. In some cases, your doctor may recommend that you switch to a different antidepressant.

Synthroid and certain antidepressants that increase levels of Synthroid. Tricyclic antidepressants TCAs and tetracyclic antidepressants may interact with Synthroid.

If you take these drugs with Synthroid, the levels of both Synthroid and the antidepressant may be increased in your body. This means you may have an increased risk of side effects from both medications. And keep in mind that side effects of Synthroid can include serious conditions, such as irregular heartbeat.

The antidepressant sertraline Zoloft may also interact with Synthroid. However, this drug may decrease the level of Synthroid in your body. This can make Synthroid less effective for you. Certain medications used to treat high cholesterol may interact with Synthroid.

In fact, certain cholesterol medications called bile acid sequestrants can decrease the level of Synthroid in your body. These cholesterol drugs may do this by lowering the amount of Synthroid that your body absorbs.

If you take a bile acid sequestrant, your doctor may recommend that you take Synthroid at least 4 hours before you take the bile acid sequestrant. Doing this helps to lower your risk of this drug interaction. And your doctor may also order blood tests more often than usual to monitor your thyroid health. Certain medications that affect your electrolyte levels may interact with Synthroid.

Examples of these medications include:. These medications may decrease the amount of Synthroid that your body absorbs. This can lower the level of Synthroid in your body, making the drug less effective for you. And your doctor may adjust your dosage of Synthroid needed. Phenobarbital, a drug used to treat seizures , may decrease the level of Synthroid in your body.

This could make Synthroid less effective for you. An antibiotic called rifampin Rimactane may decrease the level of Synthroid in your body.

If you take Synthroid with rifampin, your doctor may order blood tests more often than usual to monitor your thyroid health. If taken with certain anticoagulants that affect your vitamin K level, Synthroid may increase the effect of the anticoagulant drug in your body.

Anticoagulants are blood thinners. This means that Synthroid may make certain anticoagulants, such as warfarin Coumadin , work better than they usually do. And this may cause your blood to become too thin, which can lead to serious side effects, such as internal bleeding. Synthroid may decrease the level of digoxin Lanoxin in your body. Digoxin is used to treat certain heart conditions.

With this interaction, digoxin may not work as well as usual. In some cases, your doctor may increase your dosage of digoxin. Taking certain birth control drugs that contain estrogen may decrease the level of certain hormones in your body.

This interaction can affect your level of both Synthroid and the birth control medication. In some cases, your doctor may adjust your dosage of Synthroid. Or they may recommend that you use a different birth control option.

Certain mineral supplements may interact with Synthroid. Certain mineral supplements interact with Synthroid by binding to Synthroid inside your stomach. Doing so will help make sure your dose of Synthroid is absorbed like usual. If you have any questions about taking Synthroid with mineral supplements, talk with your doctor.

These foods may interact with the drug and change the level of Synthroid in your body. Coffee may decrease the amount of Synthroid that your body absorbs. This means that if you drink coffee with your dose of Synthroid, you may not be getting the full amount of Synthroid in your dose. In this case, Synthroid may not work as well as usual for you. Your doctor may recommend that you take your doses of Synthroid at different times than when you drink coffee.

Grapefruit and grapefruit juice may both interact with Synthroid, decreasing the level of Synthroid in your body. If your Synthroid level is decreased, the drug may not work as well as usual for you.

Your doctor may recommend that you take your doses of Synthroid at different times than when you consume grapefruit. Or they may recommend that you avoid the fruit altogether. Soybeans and soybean flour may bind to Synthroid inside your stomach and stop your body from absorbing the drug properly. If you eat soybeans or soybean flour, your doctor may increase your dosage of Synthroid.

Doing this will help to make sure that you have enough of the medication in your system. Your doctor may also order certain blood tests more often than usual to monitor your thyroid. Synthroid may be affected by cottonseed meal.

This product may bind to Synthroid inside your stomach and lower the amount of Synthroid your body absorbs. In this case, you may not have enough Synthroid in your body to treat your condition. If you eat cottonseed meal, your doctor may increase your dosage of Synthroid. Or they may recommend that you decrease the amount of cottonseed meal in your diet.

Your doctor may also check certain blood tests more often than usual to monitor your thyroid. Walnuts can bind to Synthroid inside your stomach and lower the amount of Synthroid that your body absorbs. Or they may recommend that you eat other nuts instead. If you do eat walnuts, your doctor may order certain blood tests more often than usual to monitor your thyroid.

Dietary fiber may bind to Synthroid inside your stomach, which can lower the amount of Synthroid your body absorbs. Dietary fiber is fiber that you consume from eating certain foods. Your doctor may also recommend that you decrease your fiber intake. And they may order certain blood tests more often than usual to monitor your thyroid. Synthroid may affect certain blood tests, such as those used to check your thyroid hormone levels.

In addition, a supplement called biotin may interact with labs that are used to check thyroid hormone levels. Both of these interactions are described below. Biotin supplements may affect the blood tests used to check thyroid hormone levels.

In fact, biotin may cause certain blood tests to show a high level of thyroid hormone in your body. But this interaction is just between the blood test and the biotin supplement. If you take biotin, your doctor may have you take less of the supplement for a few days before you have labs to check your thyroid.

Or your doctor may recommend that you stop taking the biotin supplement before your labs. This is done to be sure that your levels are within a normal range. But keep in mind that Synthroid is a man-made form of the natural thyroid hormone called T4.

This means that if you take the drug before having blood work, your T4 level may be falsely elevated. Before having blood tests to check your thyroid, ask your doctor if you should take your Synthroid doses as usual. Your doctor will recommend when you should take your Synthroid dose in relation to when your labs will be done.

Synthroid comes as tablets that are taken by mouth. Synthroid should be taken once daily on an empty stomach. In some cases, your doctor may discuss with you how to take Synthroid at night. You should take Synthroid on an empty stomach without food. If you do eat something, and you forget to take Synthroid, call your doctor or pharmacist.

This length of time may depend on the type of food you ate and whether you took any other medications. You may need to wait 4 hours to take your Synthroid after eating. If you have questions about when to take Synthroid around meals, talk with your doctor or pharmacist. Yes, you can crush, split, or chew Synthroid tablets. For example, to give the drug to children or infants, Synthroid tablets can be crushed and dissolved in 1 to 2 teaspoons 5 to 10 mL of water.

This is because Synthroid should be taken on an empty stomach. Synthroid may also be used off-label for other conditions. Synthroid is approved to treat hypothyroidism. With this condition, you can have symptoms such as tiredness and weight gain. You may also have muscle weakness and constipation. Thyroid hormones are very important to your health because they regulate your metabolism all of the chemical reactions in your body.

The two main thyroid hormones in your body are called T3 and T4. Synthroid is a man-made form of T4, and it works by replacing T4 in your body. Your body then uses T4 to make T3. These different types of hypothyroidism have different causes. However, Synthroid works the same way no matter the cause of the condition.

Despite this lack of clinical trials, levothyroxine the active drug in Synthroid is recommended as the primary treatment for hypothyroidism. In , the American Thyroid Association released guidelines showing the best treatments for hypothyroidism.

These guidelines state that products that contain levothyroxine should be used as the standard treatment for hypothyroidism. The years of use have shown that levothyroxine reduces symptoms of hypothyroidism in most people. In addition, levothyroxine treatment has been shown to be safe and without many serious side effects. T4 was first recognized in the human body in , and a man-made form of it called levothyroxine was first made in In , new laws were created by the FDA.

Synthroid is approved to suppress decrease levels of thyroid stimulating hormone TSH. TSH stimulates your thyroid to make thyroid hormones. The two main thyroid hormones in your body are T3 and T4.

In addition, TSH is responsible for growth of cells in your thyroid gland, including growth of cancerous cells. By decreasing your TSH level, Synthroid can help decrease the growth of certain types of thyroid cancer.

Normally, when your thyroid hormone levels are low, your body makes TSH. This signals your thyroid to make more thyroid hormones. With a lower TSH level, growth of cancer in your thyroid may decrease. When Synthroid is used for TSH suppression, the drug is meant to be used along with surgery and radioactive iodine treatment.

According to the American Thyroid Association , TSH suppression is recommended in some people with high-risk forms of thyroid cancer. Levothyroxine is the recommended drug to use alongside surgery and radioactive iodine treatment. However, levothyroxine is considered the recommended drug for this use. In addition to the uses listed above, Synthroid may be used off-label for other purposes.

And you may wonder if Synthroid is used for certain other conditions. With this condition, you have increased levels of thyroid hormones in your body. The two main thyroid hormones are T3 and T4.

Instead, Synthroid is FDA-approved to treat hypothyroidism , which is the opposite of hyperthyroidism. With hypothyroidism, you have low levels of thyroid hormone. Synthroid is a man-made form of T4. It replaces or adds to your natural thyroid hormones, which helps your body to have the right amount of T4. Your body then uses the T4 to make T3. This raises your risk of serious side effects, such as tremors, anxiety, and irregular heart rate.

If you have hyperthyroidism, talk with your doctor about appropriate treatment options for your condition. In some cases, children may need to take Synthroid for certain problems affecting their thyroid.

Below, we describe approved uses of Synthroid for children. From birth, some children may not be able to make enough thyroid hormones. This condition is called congenital hypothyroidism. Usually, for congenital hypothyroidism, a child will take Synthroid for their entire life. Synthroid works by replacing T4, one of the main thyroid hormones. And their body then uses T4 to make T3, which is the other main thyroid hormone.

Children may also acquire develop hypothyroidism during their childhood. This may occur because of changes in their thyroid or pituitary. The pituitary tells the thyroid to make thyroid hormones.

In some cases, your doctor may recommend that you take other medications with Synthroid. Below, we describe some supplements that your doctor may recommend. However, before starting any of these supplements, be sure to talk with your doctor.

Vitamin D plays a role in how your immune system functions. And because some thyroid conditions are related to your immune system, people with these conditions may have low vitamin D levels. If you have hypothyroidism, your doctor may order blood tests to check your vitamin D level. And your doctor may recommend that you take a vitamin D supplement if your levels are low. For some people, increasing vitamin D level may help decrease symptoms of their thyroid condition.

It makes you feel sleepy when it gets dark outside. One study showed that melatonin may increase your levels of T4.

T4 is one of the main thyroid hormones in your body, which Synthroid is used to replace or add to. And the study showed that melatonin may also decrease feelings of anxiety and depression. In some cases, your doctor may recommend that you take a melatonin supplement along with Synthroid. But keep in mind that melatonin may affect your thyroid hormone levels. Because of this, your doctor may check your thyroid hormone levels when you first start taking melatonin.

Sometimes hypothyroidism may cause problems with your intestines. This may happen because decreased thyroid function is linked to having too much bacteria in your small intestine. And having large amounts of bacteria in your intestine may result in certain problems, such as diarrhea. Taking a probiotic may help to decrease harmful bacteria and increase helpful bacteria in your gut. Synthroid is a man-made form of a natural thyroid hormone called T4.

Below, we describe how Synthroid works for each of these uses. The main thyroid hormones in your body are T3 and T4. And your body then uses T4 to make T3. Synthroid helps to bring your thyroid hormone levels back to a normal range.

And it also helps reduce your symptoms of hypothyroidism. Synthroid is used to suppress lower TSH levels in people with thyrotropin-dependent well-differentiated thyroid cancer.

TSH stimulates your thyroid to make more thyroid hormones. In addition, TSH is responsible for cell growth in your thyroid gland.