Brand Name vs Generic Levothyroxine: What’s the Difference?

The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so. You will receive a few doses of this medicine, then your doctor may switch you to an oral dosage form. Because levothyroxine can cause side effects including anxiety, heat intolerance, and diarrhea—and in extreme cases, cardiovascular morbidity and death, especially in those over 80—this finding is alarming, says El-Khoury.

Acute adrenal crisis in patients with concomitant adrenal insufficiency

Protein-bound thyroid hormones exist in reverse equilibrium with small amounts of free hormone. Many drugs and physiologic conditions affect the binding of thyroid hormones to serum proteins see DRUG INTERACTIONS. Thyroid hormones do not readily cross the placental barrier see Use In Specific Populations. Published studies report that levothyroxine is present in human milk following the administration of oral levothyroxine. No adverse effects on the breastfed infant have been reported and there is no information on the effects of levothyroxine on milk production.

• But there is some controversy about whether it’s as effective and reliable as the brand-name versions.
• But that difference could add up to the equivalent of anywhere from about half a pill less to an entire pill more than your intended dosage over the course of a week—even if you take your usual dosage as prescribed.
• If the results show that TSH is high and T-4 is low, then the diagnosis is hypothyroidism.
• Notify your doctor if you experience serious side effects of Synthroid including rapid heartbeat, fluttering in your chest, or chest pain.
• For instance, pill-taking behaviors, use of nutritional supplements, or patient-reported outcomes are just a few examples of data that are not captured in insurance claims data.

tablet (Euthyrox, Levolet, Levo-T, Levoxyl, Synthroid, Thyro-tabs, Unithroid, generic)

In 2016, the manufacturer of the levothyroxine brand Thyrax experienced an interruption in production that required approximately 350,000 Dutch patients to change their levothyroxine supplier. The current study examined the effect of the shortage of the levothyroxine brand Thyrax in the Netherlands and subsequent switch to a different brand on thyroid stimulating hormone (TSH) levels. El-Khoury hopes to raise awareness about the extent of this problem and encourage providers to re-test their patients at least 3 months later before initiating levothyroxine treatment.

• If you are diagnosed with subclinical hypothyroidism, talk about treatment with your health care provider.
• Toxic effects may include increased risk of cardiac arrhythmias and central nervous system stimulation.
• Also tell your health care professional if you have any other types of allergies, such as to foods, dyes, preservatives, or animals.
• Data elements include patient demographics, inpatient and outpatient services, and outpatient prescription drugs.

“But if many of those same people had gotten the same test a few months later, it would have come back as normal,” says El-Khoury. Patients suffering with hypothyroidism may experience symptoms including fatigue and depression, and in extreme cases, the condition can be debilitating. Providers diagnose hypothyroidism by first measuring TSH levels in the blood. If the level is elevated, they will conduct a second test examining Free T4 levels. If TSH is high and Free T4 is low, the provider diagnoses the patient with hypothyroidism.

Notify your doctor if you experience serious side effects of Synthroid including rapid heartbeat, fluttering in your chest, or chest pain. Help others while you gain experience across our global healthcare business. You’ll soon start receiving the latest Mayo Clinic health information you requested in your inbox.

STARTS WITH HEALTH

• Concurrent use of tricyclic (e.g., amitriptyline) or tetracyclic (e.g., maprotiline) antidepressants and SYNTHROID may increase the therapeutic and toxic effects of both drugs, possibly due to increased receptor sensitivity to catecholamines.
• “The emerging evidence is very concerning because we’re actively giving patients a drug that they don’t need that can have potentially severe side effects, especially in elderly individuals over 80,” says El-Khoury.
• Synthroid is prescribed in tablets that range from 25 to 300 mcg in strength and is usually taken once a day with a full glass of water (about 8 ounces) 30 to 60 minutes before breakfast for best adsorption into the body.
• Whatever form of levothyroxine you use, take it daily as prescribed to ensure the best results.
• Seizures have been reported rarely with the institution of levothyroxine therapy.
• The brand-name preparations of levothyroxine available in the United States for the treatment of hypothyroidism have been thoroughly tested.

Like many people, you may be in the habit of asking for the generic equivalent of a medication to save money. But if you take levothyroxine, the main drug used to treat hypothyroidism, whether to use a generic versus a name-brand drug may need to be considered carefully. If you have Hashimoto’s disease or other types of autoimmune thyroid disorders, you may be sensitive to harmful side effects from iodine.

Acute Adrenal Crisis In Patients With Concomitant Adrenal Insufficiency

These concerns were largely laid to rest in 2019 based on research published in the Mayo Clinic Proceedings. According to the analysis of over 87,000 people on either Synthroid or generic levothyroxine, there were no differences in the rate of heart attack, heart failure, atrial fibrillation, or stroke in either group. This article will tell you what you need to know about generic levothyroxine products, including their ingredients, safety, costs, and how they compare to Synthroid. Addition of levothyroxine therapy in patients with diabetes mellitus may worsen glycemic control and result in increased antidiabetic agent or insulin requirements. Carefully monitor glycemic control after starting, changing, or discontinuing SYNTHROID see DRUG INTERACTIONS. Titrate the dose of SYNTHROID carefully and monitor response to titration to avoid these effects see DOSAGE AND ADMINISTRATION.

Some patients, however, have mildly elevated TSH and normal Free T4. Providers diagnose this as subclinical hypothyroidism, and sometimes this is also treated with levothyroxine to lower TSH. “Study after study has shown that there is greater risk when you overtreat with levothyroxine in patients who may not need it,” says El-Khoury.

This leaves room for small, but meaningful, differences between levothyroxine products. The brand-name preparations of levothyroxine available in the United States for the treatment of hypothyroidism have been thoroughly tested. Most medications are available in brand-name and generic preparations.

These authorities argued that FDA policy allows potency ranges of generical synthroid pms to vary by 5%, meaning that the potency can fall anywhere from 95% and 105% of the brand-name product. With levothyroxine, either extreme can be problematic—making it harder to stabilize thyroid function if patients are underdosed with one generic and overdosed with another. According to the American Thyroid Association, primary care providers are more likely to prescribe generic levothyroxine, while specialists like endocrinologists who treat diseases like hypothyroidism are more likely to prescribe Synthroid.