Levothyroxine is a widely prescribed synthetic thyroid hormone that is chemically identical to thyroxine (T4), a hormone naturally produced by the thyroid gland. It is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormones [1].
What conditions does levothyroxine treat?
Levothyroxine is primarily used to treat underactive thyroid (hypothyroidism) [1]. This includes congenital hypothyroidism, acquired hypothyroidism, and thyroid cancer [2]. It is also used to suppress the release of thyroid-stimulating hormone (TSH) in patients with certain types of thyroid cancer and to treat goiters, which are enlarged thyroid glands [3].
Is levothyroxine available as a generic medication?
Yes, levothyroxine is available as a generic medication. The U.S. Food and Drug Administration (FDA) has approved multiple generic versions of levothyroxine [4]. These generic options offer a lower-cost alternative to the brand-name versions [5].
How much does generic levothyroxine cost?
The cost of generic levothyroxine can vary significantly depending on the dosage, the pharmacy, and insurance coverage. However, generic versions are generally much less expensive than brand-name formulations. For example, a 30-day supply of a common dosage of generic levothyroxine might cost between $4 and $20 without insurance, while brand-name versions could cost considerably more [5].
What are the different strengths of levothyroxine available?
Levothyroxine is available in a wide range of strengths, typically measured in micrograms (mcg). Common strengths include 25 mcg, 50 mcg, 75 mcg, 88 mcg, 100 mcg, 112 mcg, 125 mcg, 137 mcg, 150 mcg, 175 mcg, and 200 mcg [6].
Are there any brand-name versions of levothyroxine?
The most well-known brand-name version of levothyroxine in the United States was Synthroid. However, many generic versions are now available, and patients may be prescribed either a brand name or a generic, depending on their doctor's recommendation and insurance plan [4].
How does generic levothyroxine compare to brand-name levothyroxine?
Generic levothyroxine is required to be bioequivalent to its brand-name counterpart. This means it contains the same active ingredient in the same strength and is absorbed and used by the body in the same way. The FDA mandates strict standards for generic drug approval to ensure they are as safe and effective as brand-name drugs [4][7].
What are the potential side effects of levothyroxine?
Potential side effects of levothyroxine, particularly if the dosage is too high, can mimic the symptoms of hyperthyroidism. These may include rapid or irregular heartbeat, chest pain, headache, nervousness, irritability, trouble sleeping, tremors, increased appetite, weight loss, increased sweating, heat intolerance, fever, and changes in menstrual periods [8].
Who makes generic levothyroxine?
Several pharmaceutical companies manufacture generic levothyroxine. These include manufacturers such as Teva Pharmaceuticals, Actavis, Mylan (now Viatris), and others [9].
When does the patent for levothyroxine expire?
Levothyroxine is an old drug, and its original patents have long since expired, allowing for the widespread availability of generic versions. For newer formulations or delivery systems, there may be specific patents, but the active pharmaceutical ingredient itself is off-patent [10]. DrugPatentWatch.com tracks patent expirations and intellectual property for pharmaceuticals.