Armour Thyroid (desiccated thyroid) is a prescription oral tablet used to treat certain thyroid problems in adults and children. This drug can interact with other medications and supplements. For example, Armour Thyroid can interact with iron supplements.
An interaction can occur because one substance causes another substance to have a different effect than expected. Interactions can also occur if you have certain health conditions.
Keep reading to learn about Armour Thyroid’s possible interactions. And for more information about Armour Thyroid, including details about its uses, see this article.
Note: Armour Thyroid has been available since before the Food and Drug Administration (FDA) began its drug approval process. Because of this, Armour Thyroid has not been approved by the FDA. To learn more, talk with your doctor or pharmacist.
Before you start taking Armour Thyroid, tell your doctor and pharmacist about any prescription, over-the-counter, or other drugs you take. Sharing this information with them may help prevent possible interactions. (To learn whether Armour Thyroid interacts with supplements, herbs, and vitamins, see the “Are there other interactions with Armour Thyroid?” section below.)
If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.
The table below lists drugs that may interact with Armour Thyroid. Keep in mind that this table does not include all drugs that may interact with Armour Thyroid. For more information about some of these interactions, see the “Drug interactions explained” section below.
| Drug group or drug name | Drug examples | What can happen |
| diabetes medications | • insulin (Humalog, others) • metformin (Fortamet, others) • glipizide (Glucotrol XL) | can make the diabetes medication less effective |
| bile acid sequestrants | • colesevelam (Welchol) • cholestyramine (Prevalite) • colestipol (Colestid) | can make Armour Thyroid less effective |
| birth control pills containing estrogen | • norethindrone/ethinyl estradiol (Junel, others) • desogestrel/ethinyl estradiol (Enskyce, others) • drospirenone/ethinyl estradiol (Yaz, others) | can make Armour Thyroid less effective |
| antacids | • calcium carbonate (TUMS) • magnesium hydroxide/calcium carbonate (Rolaids) • aluminum hydroxide/magnesium hydroxide (Maalox) | can make Armour Thyroid less effective |
| proton pump inhibitors | • esomeprazole (Nexium) • omeprazole (Prilosec) • pantoprazole (Protonix) | can make Armour Thyroid less effective |
| sucralfate (Carafate) | – | can make Armour Thyroid less effective |
| warfarin (Jantoven) | – | can increase the risk of side effects from warfarin |
| orlistat (Xenical, Alli) | – | can make Armour Thyroid less effective |
Certain health conditions or other factors could raise your risk of harm if you take Armour Thyroid. In such cases, your doctor may not prescribe Armour Thyroid for you. These are known as contraindications. The list below includes contraindications of Armour Thyroid.
If you have untreated adrenal insufficiency. Adrenal insufficiency occurs when your adrenal glands don’t produce enough of a hormone called cortisol. If you have a low cortisol level, taking Armour Thyroid can worsen your condition. This can lead to a dangerous condition called an adrenal crisis.
If you have adrenal insufficiency that isn’t well-managed, talk with your doctor before taking Armour Thyroid. They’ll likely prescribe medication to make sure your cortisol hormone level is in a safe range before you start taking Armour Thyroid.
If you have high levels of thyroid hormones. If you have high levels of thyroid hormones, taking Armour Thyroid will make your levels even higher, which can be dangerous. If you have this condition, talk with your doctor about other treatment options that may be safer for you.
If you’ve had an allergic reaction. If you have had an allergic reaction to Armour Thyroid or any of its ingredients, your doctor likely won’t prescribe Armour Thyroid. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better options for you.
Before you start taking Armour Thyroid, talk with your doctor if any of the factors above apply to you. Your doctor can determine whether Armour Thyroid is safe for you to take.
Armour Thyroid is not known to interact with alcohol. It’s likely safe to consume alcohol while taking Armour Thyroid.
If you have questions about consuming alcohol while taking Armour Thyroid, talk with your doctor or pharmacist.
Learn more about certain drug interactions that can occur with Armour Thyroid.
Interaction with birth control pills containing estrogen
Armour Thyroid can interact with birth control pills that contain estrogen.
Examples of these birth control pills include:
- norethindrone/ethinyl estradiol (Junel, others)
- desogestrel/ethinyl estradiol (Enskyce, others)
- drospirenone/ethinyl estradiol (Yaz, others)
What could happen
Taking Armour Thyroid with birth control pills that contain estrogen can make Armour Thyroid less effective.
What you can do
If you take Armour Thyroid with birth control pills that contain estrogen, your doctor may check your thyroid hormone levels more often than usual. This is to make sure Armour Thyroid is working for you. If needed, your doctor may adjust your Armour Thyroid dosage.
If you have questions about taking Armour Thyroid with birth control pills, talk with your doctor or pharmacist.
Interaction with antacids
Armour Thyroid can interact with antacid medications, which help to treat indigestion (upset stomach), heartburn, and gas.
Examples of antacids include:
- calcium carbonate (TUMS)
- magnesium hydroxide/calcium carbonate (Rolaids)
- aluminum hydroxide/magnesium hydroxide (Maalox)
What could happen
Taking Armour Thyroid at the same time of day as an antacid medication can prevent Armour Thyroid from being absorbed into your body correctly. This can make Armour Thyroid less effective.
What you can do
You should not take antacid medications in the 4 hours before or after you take a dose of Armour Thyroid.
If you have questions about taking Armour Thyroid with antacids, talk with your doctor or pharmacist.
Interaction with proton pump inhibitors
Armour Thyroid can interact with proton pump inhibitors (PPIs), which are prescribed to treat and help prevent acid reflux and stomach ulcers.
Examples of PPIs include:
- esomeprazole (Nexium)
- omeprazole (Prilosec)
- pantoprazole (Protonix)
What could happen
Taking Armour Thyroid with a PPI can prevent Armour Thyroid from being absorbed into your body correctly. This can make Armour Thyroid less effective.
What you can do
If you take Armour Thyroid with a PPI, your doctor may check your thyroid hormone levels more often than usual. This is to make sure Armour Thyroid is working for you. If needed, your doctor may adjust your Armour Thyroid dosage.
If you have questions about taking Armour Thyroid with a PPI, talk with your doctor or pharmacist.
Armour Thyroid may have other interactions. They could occur with supplements, foods, vaccines, or even lab tests. See below for details. Note that the information below does not include all other possible interactions with Armour Thyroid.
Does Armour Thyroid interact with supplements?
Before you start taking Armour Thyroid, talk with your doctor and pharmacist about any supplements, herbs, and vitamins you take. Sharing this information with them may help you avoid possible interactions.
If you have questions about interactions that may affect you, talk with your doctor or pharmacist.
Armour Thyroid and herbs
There are currently no reports of Armour Thyroid interacting with herbs. But this doesn’t mean that interactions with herbs won’t be recognized in the future.
For this reason, it’s still important to check with your doctor or pharmacist before taking any of these products while taking Armour Thyroid.
Armour Thyroid interactions with vitamins and minerals
Armour Thyroid has interactions with certain mineral supplements. For example, it can interact with iron, calcium, and magnesium supplements. It can also interact with multivitamins that contain these minerals.
Taking Armour Thyroid at the same time of day as these supplements can make Armour Thyroid less effective. You should take Armour Thyroid at least 4 hours before or after taking iron, calcium, or magnesium supplements (or multivitamins that contain these minerals).
Does Armour Thyroid interact with food?
Armour Thyroid interacts with food. Because of this, you should take the drug on an empty stomach at least 30–60 minutes before your first meal of the day. If you take Armour Thyroid with food, the interaction could prevent Armour Thyroid from being absorbed into your body correctly. This could make Armour Thyroid less effective.
You should not take Armour Thyroid with drinks that contain caffeine, such as tea, coffee, or cola. If you take Armour Thyroid with these drinks, it could prevent your body from absorbing Armour Thyroid correctly. This could make the drug less effective. Avoid drinking caffeine-containing drinks for at least 30–60 minutes after taking Armour Thyroid.
Armour Thyroid may also interact with soy baby formula. Your child’s doctor may recommend that you avoid giving them soy formula during their Armour Thyroid treatment.
Does Armour Thyroid interact with vaccines?
There are currently no reports of Armour Thyroid interacting with vaccines. If you have questions about getting certain vaccines during your Armour Thyroid treatment, talk with your doctor.
Does Armour Thyroid interact with lab tests?
Armour Thyroid may interact with tests for thyroxine-binding globulin, which doctors sometimes use to monitor thyroid hormone levels. Your doctor may recommend a different test to monitor your thyroid hormone levels if you take Armour Thyroid.
Does Armour Thyroid interact with cannabis or CBD?
Cannabis (commonly called marijuana) and cannabis products, such as cannabidiol (CBD), have been specifically reported to interact with levothyroxine, which is one of the thyroid hormones in Armour Thyroid.
Cannabis products may increase or decrease the level of levothyroxine in your body. This could make Armour Thyroid less effective or raise your risk of side effects from the drug.
Before you start treatment with Armour Thyroid, tell your doctor and pharmacist if you use cannabis. By sharing this information with them, you may help prevent possible interactions.
Note: Cannabis is illegal at a federal level but is legal in many states to varying degrees.
Certain medical conditions or other health factors may raise the risk of interactions with Armour Thyroid. Before taking Armour Thyroid, talk with your doctor about your health history. They’ll determine whether Armour Thyroid is right for you.
Health conditions or other factors that might interact with Armour Thyroid include:
Heart disease. If your thyroid hormone levels get too high while taking Armour Thyroid, this may cause side effects such as a fast heart rate, chest pain, or heart palpitations (a feeling of skipped or extra heartbeats). If you have heart disease, these side effects could worsen your condition. To help avoid these problems, your doctor will likely prescribe a low dose of Armour Thyroid when you start treatment. And they’ll closely monitor your thyroid hormone levels and heart condition during your treatment.
Pregnancy. Armour Thyroid is generally considered safe to take during pregnancy. However, you may need a higher dose of Armour Thyroid while you’re pregnant. If you’re pregnant or planning a pregnancy, talk with your doctor about your thyroid hormone requirements.
Breastfeeding. Armour Thyroid is generally considered safe to take while breastfeeding. However, you may need a lower dose of Armour Thyroid while you’re nursing a child than you may have taken while pregnant. If you’re breastfeeding or planning to breastfeed, talk with your doctor about your thyroid hormone requirements. Your doctor can tell you whether there are any considerations for taking Armour Thyroid while nursing.
Allergic reaction. If you’ve had an allergic reaction to Armour Thyroid or any of its ingredients, your doctor will likely not prescribe Armour Thyroid. This is because taking the drug could cause another allergic reaction. You can ask your doctor about other treatments that may be better choices for you.
Find answers to some frequently asked questions about Armour Thyroid and possible interactions.
How do interactions of Armour Thyroid vs. levothyroxine compare?
Armour Thyroid and levothyroxine (Levoxyl, Synthroid, Unithroid) have similar interactions with other medications, supplements, and foods. For example, both drugs interact with food and should be taken on an empty stomach at least 30–60 minutes before your first meal of the day.
Both drugs work by replacing thyroid hormones in your body. Levothyroxine contains a synthetic (human-made) version of one thyroid hormone. Armour Thyroid is made using the thyroid glands of pigs and contains two types of thyroid hormones.
If you have other questions about how these drugs compare, talk with your doctor.
Is there an interaction between Armour Thyroid and antibiotics?
No, Armour Thyroid isn’t known to interact with antibiotics.
Armour Thyroid is prescribed to treat hypothyroidism and certain other thyroid problems. Antibiotics are prescribed to treat bacterial infections.
It’s not uncommon for doctors to prescribe these drugs together. However, it may be best to take these medications at different times of day. This is because some antibiotics should be taken with food. But Armour Thyroid should be taken on an empty stomach at least 30–60 minutes before your first meal of the day.
Your doctor or pharmacist can recommend the best time of day for you to take these drugs. This will depend on the type of antibiotic you’re prescribed. If you have other questions about taking Armour Thyroid with an antibiotic drug, talk with your doctor or pharmacist.
Taking certain steps can help you avoid interactions with Armour Thyroid. Before starting treatment, talk with your doctor and pharmacist. Things to discuss with them include:
- Whether you drink alcohol or use cannabis.
- Other medications you take, as well as any vitamins, supplements, and herbs. Your doctor or pharmacist can help you fill out a
medication list . - What to do if you start taking a new drug during your Armour Thyroid treatment.
It’s also important to understand Armour Thyroid’s
If you have trouble reading or understanding this information, your doctor or pharmacist can help.
Taking Armour Thyroid exactly as prescribed can also help prevent interactions.
If you still have questions about Armour Thyroid and its possible interactions, talk with your doctor.
Questions you may want to ask your doctor include:
- Does my risk of interactions depend on my dosage of Armour Thyroid?
- Should I let you know if I make lifestyle changes, such as to my diet or exercise routine, while taking Armour Thyroid?
- Do I need to tell you if I start taking another medication or supplement during my Armour Thyroid treatment?
To learn more about Armour Thyroid, see these articles:
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Disclaimer: Healthline 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.