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.
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 medicationThe correct dosageUnexpired drugsThe 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.
Taking Hypothyroidism Drugs
Medications used to treat hypothyroidism work best when you take them at the same time every day.
Levothyroxine T4/T3 combination therapy Natural desiccated thyroid drug
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.
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.
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.
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.
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 intoleranceCeliac diseaseAtrophic gastritisMalabsorption syndromesHelicobacter pylori infectionAutoimmune gastritisPancreatic diseasesLiver 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:
Crohn’s disease Ulcerative colitis Celiac disease
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 allergiesLactose, which can be a problem for those with lactose intoleranceCornstarch, 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:
NauseaVomitingChest painRapid or irregular heartbeatDiarrheaFeverTremorsHeadache
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:
Digoxin for heart problems Blood thinners, such as Coumadin (warfarin) Beta-blockers, such as Tenormin (atenolol)
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.
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.
Levothyroxine (T4), marketed under the brand names Synthroid, Levoxyl, Unithroid, and TirosintLiothyronine (T3). marketed under the brand names Cytomel and TriostatNatural desiccated thyroid (NDT)
Tapazole (methimazole)Propylthiouracil (PTU)
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