How to Take Your Thyroid Medication

Ensuring Efficacy—and Safety

Taking your thyroid medication properly helps you absorb it well and limits your risk of side effects. That's true whether you have hypothyroidism (low thyroid activity) or hyperthyroidism (high thyroid activity).

The different types of thyroid medications each have certain specifications in terms of whether they can be taken with or without food, time of day when they should be taken, drug interactions, and signs of inadequate dose or overdose.

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

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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 active drug ingredients, but other ingredients vary and may affect absorption.

Store thyroid drugs properly. Don't expose them to moisture or heat, and it's best to not keep them in the bathroom.

tips for taking thyroid medication
Illustration by Emily Roberts, Verywell

Taking Hypothyroidism Drugs

Medications used to treat hypothyroidism 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 these medications, and inadequate absorption can make them less effective.

Consistency

Missing even a day or two of thyroid medication can cause 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 and Hypothyroid Medication

See your healthcare provider right away if you become pregnant while taking medication to treat low thyroid levels. Your dose will likely need to be increased.

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 hypothyroid treatment while breastfeeding. Studies show minimal amounts get into the milk.

Switching Brands

Switching brands of levothyroxine or changing to a generic may affect your symptoms or side effects. A pharmacy can make substitutions without your healthcare provider's knowledge unless they 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 a 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 hypothyroid treatment, with consideration of your lifestyle and other medications and supplements you're taking.


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.

Food Interactions

Food can bind with thyroid medication. That can change how fast it dissolves and how it's absorbed in your intestines

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 thyroid TSH tested. Your dosage may become too high.
  • Fiber: If you increase dietary fiber, have your TSH tested to make sure your levels are stable.

Drug Interactions

Many different medications 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 advised to take these drugs at a different time from your levothyroxine, or your thyroid hormone levels may need to be monitored more closely.

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

Supplement Interactions

Many dietary supplements can interfere with the absorption or action of thyroid hormones and may affect thyroid test results.

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.
  • Vitamin C: May increase absorption. Watch for symptoms of hyperthyroidism (excess thyroid hormones).
  • Iodine or kelp: Can worsen hypothyroidism or hyperthyroidism.

If you are taking thyroid medication, talk to your healthcare provider before taking supplements.

Medical Conditions

A number of medical conditions may affect the absorption of thyroid medications and change the effectiveness of your medication.

Some of these include:

  • Lactose intolerance
  • Celiac disease
  • Atrophic gastritis
  • Malabsorption syndromes
  • Helicobacter pylori infection
  • Autoimmune gastritis
  • Pancreatic diseases
  • Liver disease

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

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

Different forms of thyroid medication

  • The liquid or gel cap form of levothyroxine may be better absorbed than levothyroxine pills.
  • With natural desiccated thyroid medications, debate exists over whether taking it sublingually (under the tongue) gets it into the bloodstream faster.

Potential Allergies

While uncommon, allergic reactions or sensitivities to 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 or sensitivities.

Taking Your Medication for Hyperthyroidism

Taking medication for treating hyperthyroidism (overactive thyroid) is simpler than taking medication for treating 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 regarding missed doses 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 that may include:

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

MMI and PTU

Since Tapazole (methimazole or MMI) and PTU (propylthiouracil) should be taken consistently, 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.

Medication Interactions

Some drugs can interact with hyperthyroidism treatments:

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 before taking a new medication or supplement, even if it's over the counter.

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.

Rare, but serious reactions 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.

If you develop agranulocytosis, it's important to avoid exposure to people who are sick. Also, be sure to stay up-to-date on immunizations.

Summary

Thyroid drugs work best when taken correctly. 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. Watch for negative side effects and drug interactions.

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.

For hyperthyroidism treatments, make sure you don't double up on natural T3 drugs. That can cause an overdose. You need to take Tapazole and PTU consistently. Figure out ways to remind yourself so you can be consistent.

A Word From Verywell


Thyroid medication, when used correctly, has a beneficial impact on quality of life. Some factors can change your thyroid medication dosing needs—weight changes, pregnancy, digestive issues, and more.

In order to get the full benefit of your thyroid medication, it's important to understand how and when to take it, what to do if you miss a dose, and the signs that your dose is too high or too low.

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:

    • Levothyroxine (T4), marketed under the brand names Synthroid, Levoxyl, Unithroid, and Tirosint
    • Liothyronine (T3). marketed under the brand names Cytomel and Triostat
    • Natural desiccated thyroid (NDT)
  • 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.

  • 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. 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.

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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.
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