Common Thyroid Medication Mistakes

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Instructions for taking thyroid hormone replacement drugs like Synthroid (levothyroxine) and Cytomel (liothyronine/T3) are very specific for good reason. Even making what may seem like minor mistakes when taking your thyroid medication can influence how well your body absorbs it, and failing to get the full dose of your medication can throw your hormone levels out of balance.

It's well worth being aware of these more common medication mistakes that can influence the management of your thyroid disease so you can ensure that you're doing all you can to help your hormone replacement drug do its job properly.

Being Inconsistent

Hypothyroidism is, in most cases, a lifelong condition that must be strictly managed. It's essential to take your prescribed dosage daily and at the same time each day.

You also want to be consistent about other issues, such as whether you take your medication with or without food, and before or after starting or stopping a high-fiber diet.

Some people find it difficult to get into a routine of taking thyroid medication daily and at the same time each day. If you can relate, keeping your medication in one place all the time may help; setting an alarm on your cell phone may also help you remember to take your dose.

Stopping or Reducing Your Medication

Some people decide to go off their thyroid medications altogether without talking to their doctor. This can be particularly dangerous if you have a surgically removed or radioactive ablated thyroid, or if your thyroid is atrophied or underactive due to Hashimoto's disease.

When you don't take your thyroid medications, you may not only experience symptoms of hypothyroidism but see a rise in your cholesterol and even your risk for heart disease.

In the past, some people believed that minimizing the dose of thyroid replacement might reduce the risk of heart-related issues, but the opposite may actually be true.

While excess doses of thyroid replacement are unhealthy, taking a lower than needed dose is not healthier than taking the dose that normalizes your thyroid tests.

Pregnancy and Breastfeeding

Some women mistakenly think that thyroid hormone drugs are dangerous to a baby during pregnancy or breastfeeding and wonder if they should discontinue their use. The opposite is actually true. Taking the appropriate dose of thyroid medication is essential for a healthy pregnancy and baby, and most often thyroid hormones doses need to be increased when a woman learns she is pregnant.

If you feel anxious about taking a medication during pregnancy, keep in mind that you are simply replacing a hormone that your body is not making in adequate amounts.

Eating too Soon After Your Dose

Ideally, you should take your thyroid medication in the morning and wait an hour before eating. (If you absolutely must eat sooner than that, make sure you do this consistently.) This helps ensure that the drug is properly absorbed in the intestine, so you get your full dose.

That said, some foods should only be eaten at least three to four hours after thyroid medication. Examples include calcium-enriched foods such as high-calcium orange juice and Greek yogurt, as well as fiber-rich foods.

Overdoing It on Goitrogenic Foods

Goitrogens are substances found in some foods that have an anti-thyroid effect, which can compromise the overall efficacy of your treatment. Examples include cruciferous vegetables (broccoli, cauliflower, cabbage, kale, and others), berries, and green tea—foods that are usually highly recommended as part of a healthy, cancer-prevention diet.

You shouldn't try to avoid these foods altogether, but you may want to spread them out so you aren't eating large amounts during any single meal. The same appears to be true with soy foods, in which moderation, when you have thyroid disease, appears to be key.

Drinking Coffee With Your Thyroid Medication

Coffee can also interfere with the absorption of thyroid medications. If you can't wait an hour to have your early-morning coffee, there are a few options you may wish to discuss with your doctor. Tirosint, a liquid-cap form of levothyroxine, appears to be unaffected by coffee.

If you are taking a different brand of levothyroxine and don't want to change, you can also talk to your doctor about whether to take your thyroid medication at bedtime.

Not Considering Other Medications You're Taking

Medications, like food, should be taken at least an hour after taking thyroid medications to avoid absorption issues. But with some drugs, waiting even longer is important. For example, you should wait at least two to three hours after taking thyroid replacement medications before using antacids.

There are many medications that can interact with thyroid hormones, either increasing or decreasing the amount available to your body. Common examples include antidepressants, proton pump inhibitors, diabetes medications, and more.

drugs that may interfere with thyroid medication
Illustration by Emily Roberts, Verywell

HRT and Birth Control

Women taking estrogen—hormone replacement therapy (HRT) or the birth control pill—may need more thyroid replacement hormone. Estrogen increases the body's production of a protein that binds thyroid hormone, making it inactive. To compensate for this binding, the dose of thyroid hormone may need to be increased slightly. After a woman starts or stops taking oral contraceptives or hormone replacement therapy, thyroid levels should be tested to determine if there is an impact on thyroid function.

Be sure that the doctor prescribing your thyroid medication and monitoring your thyroid disease is aware of these and any other drugs you are taking.

Switching Brands of Levothyroxine Without Careful Follow-Up

Brand name levothyroxine is typically consistent, in terms of potency, from refill to refill. That is not always the case, however, with generics.

For some people, the variation in consistency from one maker of generic levothyroxine to another can have a negative impact on proper thyroid replacement. If you have this experience, you may want to ask your doctor about writing a "dispense as written/no substitutions" prescription for a brand name levothyroxine. If you do switch medications, either brand names or generics, it's important to follow-up with your doctor to have your thyroid tested (usually 6 weeks after the change is made), and then at regular intervals (often every 6 weeks) until your levels are stable.

Assuming "Normal" Labs Means Your Dose Is Optimal

While the reference ranges for thyroid tests often give a TSH range of 0.4 to 5.0, the fact that 95 percent of people without thyroid disease have a TSH between 0.4 and 2.5 has led some researchers to believe a goal TSH in this range may be optimal.

Talk to your doctor about what the optimal TSH level is for you as an individual and whether or not your current thyroid hormone replacement medication needs to be adjusted accordingly.

A person who continues to have hypothyroidism symptoms with a high-normal TSH, for example, may benefit from getting their TSH closer to 1.0.

Also note that, for some people, checking additional thyroid tests, such as T4, free T4, T3, free T3, and thyroid autoantibodies may be beneficial even if TSH is normal.

A Word From Verywell

It's clear that there are many potential ways that you can end up getting less of your thyroid hormone than intended, even if you are working with your doctor to make sure you are on a dose that is ideal for you to begin with. In addition, the dose of thyroid hormone that you require can change at different times in your life.

Paying attention to any symptoms you are experiencing can give you clues as to whether you may be overmedicated or undermedicated. Symptoms, after all, are our bodies way of alerting us that something's not right.

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