How to Take Your Thyroid Medication

Ensuring Efficacy—and Safety

Taking your thyroid medication may seem fairly simple. But you need to know several things to make sure the drug works like it should.

That's true whether you have:

  • Hypothyroidism (low thyroid activity)
  • Hyperthyroidism (high thyroid activity)

Taking the medication properly helps you absorb it well and limits your risk of side effects.

This article will walk you through what to do and what to avoid when you're taking thyroid medication.

4:47

3 Women Share Their Thyroidectomy Experiences

Handling Your Prescription

Doing things right starts when you get your thyroid drug. Whether you're just starting it or picking up a refill, check the label to make sure you're getting:

  • The correct medication
  • The correct dosage
  • Unexpired drugs
  • The correct number of pills

Also, check for substitutions. Different brands and generics contain the same drug. But other ingredients vary and may affect absorption.

Store thyroid drugs properly. Don't expose them to moisture or long periods of heat. It's best to not keep them in the bathroom.

tips for taking thyroid medication
Illustration by Emily Roberts, Verywell

Taking Hypothyroidism Drugs

These drugs work best when you take them at the same time every day.

Some foods, medications, supplements, and medical conditions may impair how well your body absorbs thyroid drugs. Poor absorption can make your medicines less effective.

Consistency

Missing even a day or two of your thyroid drugs can stir up symptoms. To be consistent, try to pair taking your medication with something you do every day, such as brushing your teeth. That can help you establish the habit.

If you're forgetful, try setting an alarm on your phone.

Changes Over Time

Your proper dose of thyroid drugs may change over time. If you develop new or worsening symptoms, see your healthcare provider—even if you're not due for a visit.

Pregnancy Concerns

See your healthcare provider right away if you become pregnant while on thyroid drugs. Your dose will likely need to be increased. It typically goes up about 20%.

Your health team may want to keep a closer eye on your thyroid levels while you're expecting.

It's considered safe to take your thyroid medication while breastfeeding. Studies show minimal amounts get into your milk.

Switching Brands

Switching brands of levothyroxine or changing to a generic may affect how they feel. The pharmacy can make substitutions without your healthcare provider's knowledge.

To avoid this, ask your prescriber to write "dispense as written/no substitutions" on your prescription.

Not All Levothyroxine Is Equal

The amount of levothyroxine in a tablet can differ. For example, a 100 mcg tablet may contain between 95 mcg and 105 mcg of hormone.

Timing

It's usually recommended that you take levothyroxine in the morning. If you follow that advice, take it on an empty stomach. Then avoid food and drink, including coffee, for at least an hour.

Some recent research supports taking thyroid medication at bedtime to maximize absorption. If you take combination T3/T4 therapy or desiccated thyroid, it might keep you awake.

Talk to your healthcare provider to figure out the best time for you to take your thyroid drug. Consider your lifestyle and other medications and supplements you're on.

Recap

Drugs for both hypothyroidism and hyperthyroidism work better if they're taken correctly. That starts with verifying your prescription is filled right. For hypothyroidism, be consistent about time. Watch for brand-switching by the pharmacy, which can impact how you feel. Ask whether you should take it in the morning or at night. Tell your provider if you're pregnant as you'll likely need a dosage increase.

Food Interactions

Food can affect the absorption of thyroid hormone by binding with it. That can change how fast it dissolves and keep your intestine from absorbing it properly. A few simple dietary changes can help.

  • Calcium: Don't eat high-calcium foods within three hours of your thyroid drugs.
  • Fat: Fat can interfere with absorption. If you go from a high-fat diet to a low-fat diet, have your thyroidTSH tested. Your dosage may become too high.
  • Fiber: If you increase dietary fiber, have your TSH tested to make sure your levels are stable.
  • Goitrogenic foods: Some common foods have effects similar to antithyroid drugs. Eat them in moderation. Cooking or blanching reduces the effects.
FOODS RICH IN GOITROGENS
VEGETABLES
Broccoli and broccolini
Brussels sprouts
Cabbage
Canola
Cauliflower
Collard greens
Corn
Kale
Mustard greens
Spinach
Sweet potatoes
FRUITS
Peaches
Pears
Strawberries
PROTEINS
Flax
Lima beans
Peanuts
Pine nuts
Soy and soy-based foods

Drug Interactions

Several hundred drugs interact with thyroid medications. They include prescription and over-the-counter products.

Go over your possible interactions and what to do about them with your healthcare provider and pharmacist whenever you start a new medication.

You may be able to take the drug, but your thyroid hormone levels may need to be monitored more closely. You may also want to take these drugs at a different time from your levothyroxine.

DRUG CLASS  TREATS EXAMPLES NOTES
Selective serotonin reuptake inhibitors (SSRIs) Depression Anxiety Zoloft (sertraline) Celexa (citalopram) Levothyroxine dosage may need to increase
Tricyclic antidepressants Depression Other mental disorders Elavil (amitriptyline) Sinequan (doxepin) Norpramin (desipramine) Can increase potency of both drugs
Proton pump inhibitors Acid reflux Peptic ulcers Prilosec (omeprazole) Prevacid (lansoprazole) Nexium (esomeprazole) Levothyroxine dosage may need to increase
Insulins Diabetes Humalog (insulin lispro) Humulin N (human insulin isophane) Dosage of both drugs may need to increase
Antidiabetics Diabetes Glucophage (metformin) Dosage of both drugs may need to increase
Estrogens Birth control Hormone replacement Ortho-Novum (ethinyl estradiol/norethindrone) Premarin (conjugated estrogens) Levothyroxine dosage may need to increase
Statins High cholesterol Questran (cholestyramine) Colestid (colestipol) Take at least 4 hours after levothyroxine
Anticoagulants (blood thinners) Blood clotting Heart disease Coumadin (warfarin) Heparin Anticoagulant dosage may need to decrease
Antacids Heartburn Acid reflux Tums (calcium carbonate) Mylanta (aluminum hydroxide, magnesium hydroxide) Take at least 3 hours after levothyroxine

Many other drugs may interfere with thyroid hormones. Some that cause significant interactions include:

A wealth of other drugs can interact with thyroid medicines, as well.

Supplement Interactions

Many dietary supplements can interfere with the absorption or action of thyroid hormones or affect thyroid testing. Some of the more common ones include:

  • Calcium: Take at least three hours after thyroid hormones.
  • Iron: Wait at least two hours after taking your thyroid medication.
  • Biotin: Take at least an hour after thyroid hormones. Can interfere with thyroid testing; alert your healthcare provider that you're taking it when tests are ordered. and cause abnormal results.
  • Vitamin C: May increase absorption. Watch for symptoms of hyperthyroidism (excess thyroid hormones).
  • Iodine or kelp: Can irritate the thyroid gland.

Check supplements for potentially problematic ingredients and talk to your healthcare provider before taking them.

Medical Conditions

A number of medical conditions may affect the absorption of thyroid medications and change the effectiveness of your dose. Some of these include:

Polymorphisms (genetic differences) can lower the effectiveness of thyroid hormone in some people. One example is differences in a gene called iodothyronine deiodinase 2 (DIO2). DIO2 affects how your body converts T4 into T3, which is the active form of the hormone.

The drug levothyroxine brand Tirosint has fewer ingredients and may be better tolerated by people with digestive conditions including:

Also, the liquid or gel cap form of levothyroxine may be better absorbed than levothyroxine pills.

If you have any of these conditions, your healthcare provider may want to test your thyroid levels more frequently.

Potential Allergies

While uncommon, allergic reactions or sensitivities to levothyroid or the inactive ingredients in thyroid medications are possible.

For example, the brand Synthroid contains:

  • Acacia, which can cause allergies in some people with tree or grass allergies
  • Lactose, which can be a problem for those with lactose intolerance
  • Cornstarch, which can affect those with a corn allergy and possibly some people with gluten sensitivity

Always let your healthcare provider and pharmacist know about your medicine and food allergies.

Oral vs. Sublingual Delivery

With natural desiccated thyroid medications, debate exists over whether taking it sublingually (under the tongue) gets it into the bloodstream faster. The counterargument is that it could lead to irregular absorption.

Talk to your healthcare provider about how to take your medication and whether you'd need more frequent thyroid tests.

Recap

Foods, drugs, supplements, and medical conditions all can interfere with absorption. Allergies are possible. Check in with your provider and pharmacist about anything new you're taking, and whether you should swallow it or take it sublingually.

Taking Your Medication for Hyperthyroidism

Medication for hyperthyroidism (overactive thyroid) is simpler than for hypothyroidism. Still, you should keep some considerations in mind to ensure your medication is working as well as possible.

Forgetting Your Medication

Consistently taking your medication is important. The guidelines depend on what kind you're taking.

Natural T3 Drugs

If you're on a natural T3 medication, such as Armour or Nature Thyroid, and forget your medication, don't take your dose late or double up.

Taking more than a single dose can cause overdose symptoms. They include:

  • Nausea
  • Vomiting
  • Chest pain
  • Rapid or irregular heartbeat
  • Diarrhea
  • Fever
  • Tremors
  • Headache

MMI and PTU

Tapazole (methimazole or MMI) and PTU (propylthiouracil) are usually taken three times a day. It's important that you find ways to remember each dosage.

You may want to set alarms on your phone or find an app to send you reminders. It's a good idea to carry your medication with you so you can take it on the go.

Levothyroxine

If you take thyroid replacement hormones (levothyroxine) after surgery or radioactive iodine, you can take two pills at the same time if you forget one.

While this is safe, it's better if you remember to take it every day.

Medication Interactions

Many drugs that can interact with hyperthyroid medications. Always talk to your healthcare provider before you take anything new. Common interactions include drugs such as:

Be cautious with over-the-counter cold medications or any drugs with a stimulant effect. It's always a good idea to check in with your provider or pharmacist.

Pregnant?

If you get pregnant or suspect you are while taking Tapazole (methimazole or MMI), stop your medication and contact your healthcare provider immediately.

Adverse Reactions

It's possible to have serious side effects from anti-thyroid drugs. Be on the lookout for potential symptoms. The most common ones include:

  • Liver toxicity: Signs include abdominal pain, dark urine, jaundice (yellowed skin and whites of the eyes), and clay-colored stools.
  • Agranulocytosis (low white blood cells): Watch for fever and other signs of infection, such as a sore throat, cough, pain with urination, and headache.

It's important while you're taking these drugs to avoid close contact with people who are sick. Also be sure to stay up-to-date on immunizations.

Recap

If you forget a dose of natural T3 drugs, don't take it late or take two pills the next day. That can lead to overdose symptoms. Because Tapazole and PTU are taken three times a day, it's important to find ways to remember to take it on time. Levothyroxine can be doubled up if you miss a day.

Drug interactions and negative side effects are possible with anti-thyroid drugs. Keep an eye out for potential problems.

Summary

Thyroid drugs work best when taken correctly. For hypothyroidism drugs, ask what time of day is best to take them and be consistent about the time. If you get pregnant, you may need to increase your dosage.

Goitrogenic foods, certain drugs and supplements, and some medical conditions can make you absorb more or less of the drug. Check with your provider any time you change your medication or supplement regimen.

For hyperthyroidism drugs, make sure you don't double up on natural T3 drugs. That can cause an overdose.

You need to take Tapazole and PTU three times a day. Figure out ways to remind yourself so you can be consistent. Levothyroxine can be doubled up if you miss one.

Watch for negative side effects and drug interactions.

A Word From Verywell

In order to get the full benefit of your thyroid medication, it's important to understand how and when to take it. That'll ensure it gets into your bloodstream and does its job.

If you think your thyroid medication isn't working, look at how you're taking it and see if you could improve your routine. Look over list of side effects and interactions to if something could be interfering.

If you don't spot a problem you can solve, contact your healthcare provider. They're your partner in ensuring your medications are safe and effective so they can improve your health and functionality.

Frequently Asked Questions

  • What drugs are used to treat hypothyroidism?

    Hypothyroidism (low thyroid function) is treated with one or more of the following thyroid hormone replacement drugs:

  • What drugs are used to treat hyperthyroidism?

    Hyperthyroidism (overactive thyroid) is treated with antithyroid drugs that block the production of the thyroid hormones T3 and T4, namely:

    • Tapazole (methimazole)
    • Propylthiouracil (PTU)
  • Are thyroid replacement hormones taken with or without food?

    Levothyroxine should be taken on an empty stomach. Liothyronine can be taken with or without food. Avoid taking the drugs within three hours of eating high-calcium foods that can reduce absorption. Soybeans, walnuts, and dietary fiber may also need to be avoided.

  • How do you give hypothyroid drugs to children?

    For children who can't swallow tablets, crush and mix levothyroxine or liothyronine with 1 to 2 teaspoons of water. Don't mix it with food or soybean-based infant formula. Give them the mixture by spoon or dropper right away. This method also works for adults who have trouble swallowing pills.

  • What drugs interact with thyroid replacement hormones?

    A number of drugs can interfere with the absorption of thyroid replacement hormones, most specifically antacids, calcium supplements, cholesterol-lowering drugs, and iron supplements. Let your healthcare provider know about any medications you take before starting levothyroxine or liothyronine.

  • Are hyperthyroid drugs taken with or without food?

    Both Tapazole (methimazole) and propylthiouracil (PTU) can be taken with or without food. Taking Tapazole with food or milk can help prevent an upset stomach.

  • What drugs can interact with hyperthyroid drugs?

    Tapazole (methimazole) and propylthiouracil (PTU) can interact with beta-blockers, digitalis, theophylline, and blood thinners like warfarin. The interactions can usually be lessened by reducing the dose of the accompanying drug.

Was this page helpful?
12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Dayan C, Panicker V. Management of hypothyroidism with combination thyroxine (T4) and triiodothyronine (T3) hormone replacement in clinical practice: a review of suggested guidance. Thyroid Res. 2018;11:1. doi:10.1186/s13044-018-0045-x

  2. American Thyroid Association. Q and A: Thyroxine preparations.

  3. Garber J, Cobin R, Gharib G, et al. Clinical practice guidelines for hypothyroidism in adults: cosponsored by the American Association of Clinical Endocrinologists and the American Thyroid AssociationThyroid. 2012;22(12):1200-35. doi:10.1089/thy.2012.0205

  4. Samarasinghe S, Meah F, Singh V, et al. Biotin interference with routine clinical immunoassays: understand the causes and mitigate the risks. Endocr Pract. 2017;23(8):989-998. doi:10.4158/EP171761.RA

  5. Skelin M, Lucijanić T, Amidžić Klarić D, et al. Factors affecting gastrointestinal absorption of levothyroxine: A reviewClin Ther. 2017;39(2):378-403. doi:10.1016/j.clinthera.2017.01.005

  6. Johns Hopkins Lupus Center. Thyroid medications.

  7. Pirola I, Formenti AM, Gandossi E, et al. Oral liquid L-thyroxine (L-t4) may be better absorbed compared to L-T4 tablets following bariatric surgery. Obes Surg. 2013;23(9):1493–1496. doi:10.1007/s11695-013-1015-y

  8. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Hyperthyroidism. Updated April 2, 2021.

  9. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Levothyroxine. Updated February 15, 2019.

  10. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Liothyronine. Updated January 15, 2018.

  11. The Pharmaceutical Journal. Thyroid dysfunction and drug interactions. Updated February 12, 2021.

  12. National Institutes of Health, U.S. National Library of Medicine: MedlinePlus. Methimazole. Updated July 15, 2017.