Armour Thyroid dosage, forms, and strengths

Armour Thyroid is a brand-name prescription drug used to treat underactive thyroid (hypothyroidism) in adults and children as young as newborns. Although the Food and Drug Administration (FDA) has not approved Armour Thyroid, it is available with a prescription. Armour Thyroid is made from pig thyroid glands that are cleaned, dried, and powdered into a product called porcine-desiccated thyroid extract (DTE). DTE tablets contain two thyroid hormones: T3 (liothyronine) and T4 (levothyroxine). 

Synthetic levothyroxine is the preferred treatment for hypothyroidism, instead of Armour Thyroid, because the manufacturing processes are more reliable than DTE tablets, and the medicine’s quality and dosages are more assured. People taking synthetic levothyroxine sometimes switch to dried thyroid because their symptoms don’t improve even though their TSH levels return to normal. Some people do improve when they switch, but some don’t. Both therapies can be effective. One study found no difference in effectiveness or side effects between synthetic levothyroxine and DTE therapy. However, safety concerns regarding DTEs like Armour Thyroid do exist based on higher T3 levels. Like levothyroxine therapy, Armour Thyroid doses are variable and taken orally once daily. 

Armour Thyroid forms and strengths

Armour Thyroid is taken by mouth as tablets. There are no alternative dosing formats. The strengths written on the packaging may confuse some people. DTE is sometimes dosed in “grains,” though the packaging will also include milligrams (mg) as a measure of the weight of the thyroid extract. One “grain” of desiccated thyroid extract, a 60 mg tablet, contains 38 micrograms (mcg) of levothyroxine and 9 mcg of liothyronine. This dose is approximately equivalent to a dose of 100 mcg of synthetic levothyroxine. 

• Tablets: 15 mg (¼ grain), 30 mg (½ grain), 60 mg (1 grain), 90 mg (1 ½ grains), 120 mg (2 grains), 180 mg (3 grains), 240 mg (4 grains), 300 mg (5 grains)

Armour Thyroid dosage for adults

Armour Thyroid treats low thyroid hormone levels, whether they result from a pituitary gland problem, autoimmune disease, thyroid cancer treatment, or other causes of reduced thyroid function. Patients take doses orally once a day. Healthcare professionals typically start with a low dose (30 mg) and gradually increase the dose by 15 mg every two to six weeks until an effective dose arrives. Most people will recover normal TSH levels and symptom relief between 60 mg (1 grain) and 120 mg (2 grains) daily.

Armour Thyroid dosage for children

Armour Thyroid can be given to children as young as newborns to treat hypothyroidism. It is not FDA-approved for use in children. Dosages can be given as a standardized dose or based on the child’s body weight.

Armour Thyroid dosage restrictions

Armour Thyroid does not have dosage restrictions or reductions for people with kidney disease or liver impairment. Because thyroid hormones affect the heart, dosage reductions may be necessary for older adults or people with cardiovascular problems such as chest pain (angina). Starting doses will be lower, and the physician may need to reduce doses if Armour Thyroid worsens heart problems. Doses may also need to be adjusted for people with diabetes mellitus if their symptoms worsen while taking Armour Thyroid. 

Armour Thyroid dosage for pets

Like physicians, veterinarians rarely use desiccated thyroid extract on dogs, cats, or other animals. Plumb’s Veterinary Manual and the Merck Veterinary Manual recommend treating hypothyroidism in animals only with synthetic levothyroxine. 

How to take Armour Thyroid

Armour Thyroid is taken orally on an empty stomach once daily. 

• Take this medicine as instructed. The prescriber will tell you how much to take. Do not take extra medicine.

• Take Armour Thyroid tablets at the same time every day.

• Take the medicine on an empty stomach.

• Take a missed dose on the scheduled day. If it's the next day, take the next dose as scheduled and skip the missed dose.

• Do not stop taking this medicine without first checking with your doctor.

Armour Thyroid dosage FAQs

How long does it take Armour Thyroid to work?

Armour Thyroid immediately improves thyroid hormone levels in the body. It may take a few weeks to arrive at the right dose that completely restores normal TSH and thyroid hormone levels. It may take at least one to three weeks for people to notice a significant improvement in their symptoms. 

What happens if I miss a dose of Armour Thyroid?

If a dose of Armour Thyroid is missed, take it when reminded if it’s still the same day to take the dose. If not, skip the missed dose and take the scheduled dose on time. Do not double the dose or take extra medicine to compensate for a missed dose.

How long can you take Armour Thyroid?

Armour Thyroid is intended for long-term use. No additional side effects due specifically to long-term use have been reported if dosing is appropriately monitored and adjusted. A healthcare professional will continue to prescribe Armour Thyroid as long as the tablets effectively control symptoms and keep side effects minimal.

How do I stop taking Armour Thyroid?

Do not stop taking Armour Thyroid unless instructed by a doctor. If Armour Thyroid is stopped without substituting another type of thyroid replacement treatment, there is a risk that low thyroid symptoms will return. Except in unusual cases, thyroid hormone replacement is usually a lifelong therapy.

The only reason to immediately stop Armour Thyroid is if it causes an allergic reaction or cardiovascular complication. In that case, immediately contact the prescribing healthcare provider or get immediate medical treatment. 

Other reasons to stop taking Armour Thyroid are if symptoms do not come under control or if side effects are intolerable. Some doctors will not prescribe Armour Thyroid, so switching doctors may end Armour Thyroid treatment. Insurance coverage may be another issue. Because Armour Thyroid is not FDA-approved, some insurance plans will not cover it. Without insurance, the average retail price for 30, 60 mg tablets of Armour Thyroid is $54.

Healthcare professionals have other thyroid medications they can use in place of Armour Thyroid. These include synthetic levothyroxine (Synthroid, Levoxyl, Unithroid, or Tirosint), T3 hormones such as Cytomel (liothyronine), or combination T3/T4 drugs such as Thyrolar (liotrix). There are also other brands of desiccated thyroid extract, including NP Thyroid and WP Thyroid.

What is the maximum dosage for Armour Thyroid?

The manufacturer has not specified a maximum dosage for Armour Thyroid, but the highest available tablet is 300 mg. Most people only need doses between 60 mg and 120 mg. Doses over 180 mg daily are not usually needed. Suppose Armour Thyroid is not working at 180 mg daily. In that case, the healthcare professional will suspect that the patient is not taking the drug as instructed or has a medical condition compromising the intestine’s absorption abilities (malabsorption syndrome). 

Can you overdose on Armour Thyroid?

An overdose of Armour Thyroid can cause serious and even life-threatening problems similar to hyperthyroidism. If too many Armour Thyroid tablets are taken, get emergency medical care. Symptoms of a thyroid hormone overdose include nervousness, agitation, racing heartbeats, and shaking hands. Serious side effects might include psychosis, seizures, or coma.

What interacts with Armour Thyroid?

Thyroid hormones interact with a few prescription medicines, including oral anticoagulants (blood thinners), insulin, and diabetes medications. The dosages of these drugs may need to be adjusted to avoid adverse effects of the drug interactions.

Anything that changes the digestive system could also affect the body’s ability to absorb Armour Thyroid hormones. These include drugs that decrease stomach acid (antacids, H2 blockers, and proton pump inhibitors) and a type of high cholesterol drug called bile acid sequestrants, such as cholestyramine and colestipol. 

Estrogens may decrease the effectiveness of Armour Thyroid, so doses may need to be increased for women taking birth control pills or hormone replacement medicines.

What happens when you mix Armour Thyroid and alcohol?

Drinking alcohol does not affect the absorption or effectiveness of Armour Thyroid or any other thyroid hormone replacement drug. However, alcohol may worsen some minor side effects of Armour Thyroid.

Is it safe to take Armour Thyroid during pregnancy?

Thyroid hormones are considered safe to take during pregnancy. Hypothyroidism is a serious risk to both the pregnancy and the fetus. Women taking thyroid hormones before becoming pregnant will usually have their dose increased when they’re pregnant. Women not taking thyroid hormones but with mildly abnormal thyroid blood tests may be prescribed a low dose to prevent overt hypothyroidism. Women with hypothyroidism will also have blood tests to spot low thyroid hormones every four weeks in the first half of the pregnancy and once again at 30 weeks of gestation. If a woman develops hypothyroidism while pregnant, thyroid hormone replacement will be necessary. 

Is it safe to take Armour Thyroid while breastfeeding?

Healthcare professionals do not consider low to moderate doses of thyroid hormones to be a risk when breastfeeding. The American Thyroid Association recommends that women with hypothyroidism take thyroid replacement hormones when breastfeeding. Restoring normal thyroid hormone levels in women with an underactive thyroid increases milk production, so taking thyroid hormones benefits lactating women. However, the manufacturer recommends that women nursing a baby first get medical advice from the prescriber before taking Armour Thyroid. 

What are the side effects of Armour Thyroid?

The most common side effects of Armour Thyroid are usually signs of too much thyroid hormone (hyperthyroidism). These include irritability, hair loss (especially in children), headache, sleeplessness, tremors, nervousness, nausea, vomiting, and weight loss. Serious adverse effects include trouble breathing, thyroid hormone poisoning (thyrotoxicosis), palpitations, chest pain (angina), high blood pressure, racing heartbeats, irregular heartbeats, heart failure, and heart attack. The prescribing doctor or pharmacist can provide additional drug information.

Sources

• Armour Thyroid, Prescriber’s Digital Reference (PDR)

• Armour Thyroid prescribing information, NIH National Library of Medicine

• A tale of two therapies—a comparison of Armour Thyroid and levothyroxine, Journal of the Endocrine Society

• Hypothyroidism, StatPearls

• Hypothyroidism treatments and medications, SingleCare

• Levothyroxine alternatives: What can I take instead of levothyroxine?, SingleCare

• Older therapies aren’t necessarily better for thyroid hormone replacement, Food and Drug Administration (FDA)