Many people suffer from a thyroid deficiency and are taken medications to make up for these deficiencies.
Levothyroxine (Synthroid) is an oral medication used to treat hypothyroidism (underactive thyroid). It’s a lab-made version of the T4 thyroid hormone.
It’s important to stick to the same levothyroxine product when you refill your prescription. For consistency’s sake, try not to switch between generic and brand-name versions.
Levothyroxine is available as a lower-cost generic. You can find it for less than $2 at certain pharmacies with a free GoodRx discount.
Millions of people take levothyroxine (Synthroid). It’s the first-choice medication for replacing or supplementing thyroid hormone in people living with hypothyroidism (underactive thyroid). Thyroid hormone is necessary to help your body use its energy correctly and keep your brain, heart, and other organs functioning as they should. When your thyroid levels are lower than normal, you can gain weight, feel tired, and find it hard to tolerate cold temperatures. You may also feel constipated or even have feelings of depression.
The good news is that taking the right amount of levothyroxine can help fix or manage these symptoms. And even though levothyroxine is one of the most commonly prescribed medications in the U.S., you may still have questions if you’re new to taking it.
10 things you should know about levothyroxine
First, the basics: levothyroxine is an oral medication that’s taken once daily. It comes in 12 different tablet doses ranging from 25 mcg to 300 mcg. Your healthcare provider will help monitor thyroid hormone levels in your blood to determine the best levothyroxine dose for you over time.
1. You can take levothyroxine in the morning or at night
You’ve probably heard the recommendation to take levothyroxine in the morning at least 30 to 60 minutes before breakfast. That’s because it’s absorbed into the body more easily on an empty stomach.
But this can be tough if you have an unpredictable schedule in the morning. In this case, you can take levothyroxine every night at bedtime instead. It’s best taken at least 4 hours after your last meal or after any doses of other medications or supplements.
Taking levothyroxine at bedtime has shown to be as effective as taking it 1 hour before breakfast. So, it doesn’t matter if you choose to take it in the morning or night. Just make sure to take it daily around the same time, separate from food and other medications.
2. It’s a lab-made version of the T4 hormone
Levothyroxine tablets are a lab-made (synthetic) version of the T4 hormone. They have the same effect as the T4 hormone made by your thyroid gland. That’s why they work so well when you don’t have enough thyroid hormone naturally.
After you swallow a levothyroxine tablet, it gets converted into T3, which is the active hormone that has an effect on the rest of the body. There are also medications, such as liothyronine (Cytomel), that supply T3.
Some people have questioned whether replacing both T3 and T4 in hypothyroidism could be beneficial, but studies don’t show an advantage to doing that. The current recommendation is to take levothyroxine alone for hypothyroidism when possible.
3. Switching between brand and generic versions can be tricky
There are a number of FDA approved name-brand levothyroxine tablets available. And unlike other brand and generic medications, they’re not easily interchangeable with generic levothyroxine. Brand names include: Synthroid, Euthyrox, Levo-T, Unithroid, Levoxyl, Tirosint
There’s an ongoing debate whether brand or generic levothyroxine is “better.” One isn’t better than the other; the answer is less about comparing the two and more about consistency in taking the same product.
It’s important to stick to the same generic product or the same brand-name product. It’s not advised to switch between the two –– even if the products appear to be equivalent –– because your thyroid levels may fluctuate.
4. You might not notice levothyroxine’s effects right away
It may take 4 to 6 weeks to see the full effect of levothyroxine. It’s important to be patient and continue taking the medication as prescribed even if you don’t notice any changes. After this time has passed, your healthcare provider may check your thyroid levels and adjust the dose of your levothyroxine accordingly.
Keep in mind, it might take months and/or multiple dose adjustments to find the right levothyroxine dose for you.
5. Levothyroxine has some side effects to be aware of
Levothyroxine is generally well-tolerated. Most of levothyroxine’s possible side effects are dose-related. When the dose is too high for your body’s needs, you could feel any of the following symptoms:
Not being able to tolerate heat, Sweating excessively, Fast heart rate or palpitations, Diarrhea, Weight loss, Nervousness or anxiety
If you feel any of these side effects, talk to your healthcare provider. Your provider can help adjust your dose as needed. More often than not, a dose adjustment takes care of these symptoms.
6. Levothyroxine interacts with some medications and foods
Levothyroxine can interact with different medications. Some medications, such as antacids, omeprazole (Prilosec), and phenobarbital, could lessen how well levothyroxine works. And this could mean you’re not getting enough thyroid hormone. But other medications, such as amiodarone (Pacerone) and beta blockers, could make its effects too strong. This could require a levothyroxine dose reduction.
Levothyroxine can also interact with certain supplements (such as iron, calcium, and vitamin C) and foods (such as coffee, grapefruit juice, and alcohol). They interfere with how well levothyroxine is absorbed into the body. That’s why it’s recommended to take it on an empty stomach, either in the morning 30 to 60 minutes before breakfast or at bedtime at least 4 hours after food or supplements.
The nice thing about levothyroxine is your healthcare provider can check your thyroid lab work and adjust the dose as needed. But it’s important to maintain consistency as much as possible with your diet, other medications, and the timing of your levothyroxine.
7. It’s safe to take in pregnancy
It’s safe to keep taking levothyroxine during pregnancy. But some extra monitoring may take place during this time. Your healthcare provider will check thyroid hormone levels as soon as you find out
you’re pregnant and may change your dose during and after your pregnancy. It’s important to repeat labs during every trimester of pregnancy and after delivery.
What’s more, some people may have newly-diagnosed hypothyroidism after they become pregnant. Levothyroxine is also safe to start taking during pregnancy.
8. Liquid levothyroxine solutions are also available
Tirosint-SOL and Thyquidity are the oral liquid forms of levothyroxine. They’re not as common as the tablets, but they can be a good option for those who have trouble swallowing pills or have severe gluten or lactose intolerance. The tablets sometimes contain gluten or lactose (depending on the product).
When you’re taking the liquid solution, you can dilute it in a small amount of water if needed. But you shouldn’t mix it with any other liquid.
9. You shouldn’t stop taking levothyroxine on your own
Taking levothyroxine every day is key to maintaining healthy levels of thyroid hormone. A study found that people who took levothyroxine more than 80% of the time had lower healthcare costs and were less likely to develop other illnesses compared to those who didn’t.
Due to findings like these, you shouldn’t stop taking levothyroxine on your own. It’s important to talk to your healthcare provider if you’re having any doubts about the tolerability or effectiveness of the medication.
10. There are ways to save on levothyroxine
There are many ways to save on levothyroxine, which is available as both a brand-name and generic medication.
Save with GoodRx. GoodRx can help you save over 89% off the average retail price of the generic version. Generic levothyroxine at certain pharmacies is less than $2 with a free GoodRx discount.
Save with patient assistance programs. If you’re uninsured or underinsured, you may be eligible for Synthroid’s patient assistance program, which offers the medication free of cost.
Save with a copay savings card. If you have commercial insurance and meet eligibility requirements, Synthroid is as little as $25 using a savings card from the manufacturer.
The bottom line
Levothyroxine is a lab-made thyroid medication used to treat hypothyroidism. It’s available as an oral tablet and liquid. The type of levothyroxine you take and the time of day you take it are important. Many things can interfere with its effectiveness if it’s not taken as directed.
Levothyroxine is usually well-tolerated. But, if the dose is too high, you may feel side effects like excessive sweating, fast heart rate, or nervousness. It’s important to notify your healthcare provider right away if you feel any of these.
8 Medications That Can Cause Hypothyroidism: Julie Hambleton
Amiodarone is a medication used to treat irregular heart rhythms, such as atrial fibrillation and ventricular tachycardia. It can also be used to prevent the recurrence of these irregular heartbeats in patients who have undergone open-heart surgery. However, amiodarone can cause hypothyroidism in some people who take it, this is because the medication is 40% iodine. Excessive iodine can cause the thyroid to shrink and lead to hypothyroidism.
Lithium is used to treat bipolar disorder, a mental illness that causes extreme shifts in mood and energy levels. Lithium can also be used to prevent recurrent mania or depression in people with bipolar disorder. However, long-term use of lithium has been linked to hypothyroidism in some cases. In fact, some studies have found that up to 50 percent of patients taking this medication develop thyroid problems within six years of starting treatment.
IODINE-containing medications, like potassium iodide (SSKI) or potassium iodate (SSKI), are used to treat thyroid conditions such as hyperthyroidism. They can also be used to prevent radiation-induced thyroid damage in people exposed to high radiation levels. However, these medications have been linked with hypothyroidism in some people.
METHIMAZOLE (Tapazole) or PROPYLTHIOURACIL (PTU) are medications that are used to treat hyperthyroidism, also known as Graves’ disease. This condition causes an overactive thyroid gland and can result in symptoms such as tremors, sweating, weight loss, and palpitations. While these drugs effectively reduce the symptoms of Graves’ disease, they can also cause hypothyroidism.
INTERFERON-alpha is a medication that’s used to treat hepatitis C and hepatitis B. It works by stopping the growth of viruses in your body, although it can also cause side effects such as joint pain, flu-like symptoms, and depression. Some people who take interferon-alpha for hepatitis C or hepatitis B may develop hypothyroidism as well.
LEVOTHYROXINE sodium tablets used to treat hypothyroidism and Hashimoto’s thyroiditis is a synthetic form of thyroid hormone that’s used to treat hypothyroidism and Hashimoto’s thyroiditis. It can cause side effects such as joint pain, nausea, vomiting, and diarrhea. Some people who take levothyroxine sodium tablets may develop hypothyroidism as well.
METFORMIN is used to treat type 2 diabetes. It can cause side effects such as joint pain, nausea, vomiting, and diarrhea. Some people who take metformin may develop hypothyroidism as well.
PRILOSEC is used to treat heartburn, acid reflux, and other stomach problems. It can cause side effects such as joint pain, nausea, vomiting, and diarrhea. Some people who take Prilosec may develop hypothyroidism as well.
As always be Safe, Stay Healthy and be Careful out there
James A Vito, D.M.D.