Thyroid Groups Issue Press Release Warning of Clinically Important Differences in Potency of FDA-Approved Levothyroxine Products
Wednesday August 11, 2004
The American Thyroid Association (ATA) and the American Association of Clinical Endocrinologists (AACE), two groups that receive extensive funding from Abbott Labs, manufacturer of Synthroid ("the most widely prescribed brand of levothyroxine") have issued another press release regarding the generic levothyroxine issue. Here is the text of the release...
Aug. 11 -- Two organizations representing more than 5,400 clinical endocrinologists today warned patients taking thyroid medication, prescribing physicians, and pharmacists dispensing these drugs that clinically important differences do, in fact, exist between one recently approved generic levothyroxine preparation and the most widely prescribed brand of levothyroxine. The members of these organizations, the American Thyroid Association (ATA) and the American Association of Clinical Endocrinologists (AACE), specialize in treatment of hormonal disorders.
Levothyroxine is taken by more than 13 million Americans to treat an underactive thyroid, thyroid gland enlargement, nodules, or cancer. In June, the Food and Drug Administration (FDA) ruled that several generic levothyroxine preparations had the same clinical effect and safety profile as certain branded products. As a result, pharmacists may substitute a patient's current levothyroxine preparation for another, sometimes without their physician's approval.
According to bioequivalence data used to acquire FDA approval, one recently approved generic levothyroxine preparation (Sandoz Levothyroxine Sodium) is significantly more potent than the most widely used brand of levothyroxine (Synthroid). Information from bioequivalence studies submitted to the FDA show that the new generic may be as much as one-eighth more potent (+12.5%) than the widely prescribed branded product.
Furthermore, levothyroxine is a drug known to have a narrow toxic-to- therapeutic ratio with significant clinical consequences of even minor excessive or inadequate dosing. Potential adverse events include symptoms, osteoporosis, atrial fibrillation, worsening of heart disease, preterm delivery in pregnancy, impaired fetal brain development, and high cholesterol.
"Unfortunately, this information confirms our concern that current FDA standards defining the equivalence of levothyroxine products is too lax," said Carlos Hamilton, MD, AACE President. "Switching between two products could compromise the effectiveness of treatment and even result in serious side effects."
The ATA and AACE have repeatedly expressed their concerns about the FDA's recent decision to approve generic substitutes for levothyroxine products and its implications for the millions of Americans who depend on this drug. The societies have also made public their disappointment that the FDA made their decision before considering the input offered by clinical endocrinologists, the recognized experts who care for thyroid patients.
Both the FDA and the societies recommend that patients switching between levothyroxine products have repeat thyroid blood testing to be certain that the treatment dose remains effective and safe. "Under a policy of allowing generic levothyroxine substitution," said Gregory Brent, MD, ATA Secretary, "more frequent thyroid function testing will be necessary. Regrettably, some patients and doctors will not even be aware of a change in preparation before adverse events occur."
The ATA and AACE advise physicians caring for patients on levothyroxine therapy to --
COMMENT FROM MARY SHOMON
The groups are right, there can be variations in potency from one levothyroxine to another. So patients do need to be aware of this potential, and make decisions regarding this with their physicians.
Unfortunately, the concern for the patients may not be the only reason behind this concerted campaign by The American Thyroid Association and the American Association of Clinical Endocrinologists. As mentioned, both groups receive extensive funding from Abbott Labs, manufacturer of Synthroid, and Synthroid is the product referred to frequently in this release as "the most widely prescribed brand of levothyroxine." Synthroid is concerned with declining market share, given that it has enjoyed a near monopoly market domination for levothyroxine, and has consistently charged substantially more than its competitors. Patients and insurers will rightly be interested in the possibility of switching to lower-cost products, if they can be used safely instead of Synthroid. Keep in mind that while being on a generic drug opens up an area of concern -- you can get a different maker's generic each time you refill -- you can switch to another brand name of levothyroxine (Levoxyl, Levothroid and Unithroid are all available in the U.S.) which will offer brandname consistency one you are stabilized on that drug -- at lower prices than Synthroid in most cases. For example, the prices at Drugstore.com for levothyroxine 112 mcg 30 tablets:
SO WHAT DOES THIS REALLY MEAN FOR PATIENTS?
See my recent article The Generics are Coming for a look at what the concerns regarding the generics really mean for you as a patient, and what you should do.
Aug. 11 -- Two organizations representing more than 5,400 clinical endocrinologists today warned patients taking thyroid medication, prescribing physicians, and pharmacists dispensing these drugs that clinically important differences do, in fact, exist between one recently approved generic levothyroxine preparation and the most widely prescribed brand of levothyroxine. The members of these organizations, the American Thyroid Association (ATA) and the American Association of Clinical Endocrinologists (AACE), specialize in treatment of hormonal disorders.
Levothyroxine is taken by more than 13 million Americans to treat an underactive thyroid, thyroid gland enlargement, nodules, or cancer. In June, the Food and Drug Administration (FDA) ruled that several generic levothyroxine preparations had the same clinical effect and safety profile as certain branded products. As a result, pharmacists may substitute a patient's current levothyroxine preparation for another, sometimes without their physician's approval.
According to bioequivalence data used to acquire FDA approval, one recently approved generic levothyroxine preparation (Sandoz Levothyroxine Sodium) is significantly more potent than the most widely used brand of levothyroxine (Synthroid). Information from bioequivalence studies submitted to the FDA show that the new generic may be as much as one-eighth more potent (+12.5%) than the widely prescribed branded product.
Furthermore, levothyroxine is a drug known to have a narrow toxic-to- therapeutic ratio with significant clinical consequences of even minor excessive or inadequate dosing. Potential adverse events include symptoms, osteoporosis, atrial fibrillation, worsening of heart disease, preterm delivery in pregnancy, impaired fetal brain development, and high cholesterol.
"Unfortunately, this information confirms our concern that current FDA standards defining the equivalence of levothyroxine products is too lax," said Carlos Hamilton, MD, AACE President. "Switching between two products could compromise the effectiveness of treatment and even result in serious side effects."
The ATA and AACE have repeatedly expressed their concerns about the FDA's recent decision to approve generic substitutes for levothyroxine products and its implications for the millions of Americans who depend on this drug. The societies have also made public their disappointment that the FDA made their decision before considering the input offered by clinical endocrinologists, the recognized experts who care for thyroid patients.
Both the FDA and the societies recommend that patients switching between levothyroxine products have repeat thyroid blood testing to be certain that the treatment dose remains effective and safe. "Under a policy of allowing generic levothyroxine substitution," said Gregory Brent, MD, ATA Secretary, "more frequent thyroid function testing will be necessary. Regrettably, some patients and doctors will not even be aware of a change in preparation before adverse events occur."
The ATA and AACE advise physicians caring for patients on levothyroxine therapy to --
- Alert patients that their levothyroxine preparation may be switched at the pharmacy,
- Encourage patients to remain on their current levothyroxine preparation when possible,
- Ensure that patients understand if they receive a new levothyroxine preparation that they will need to repeat a thyroid-stimulating hormone (TSH) blood test four to six weeks later to determine if they need further dose adjustment.
COMMENT FROM MARY SHOMON
The groups are right, there can be variations in potency from one levothyroxine to another. So patients do need to be aware of this potential, and make decisions regarding this with their physicians.
Unfortunately, the concern for the patients may not be the only reason behind this concerted campaign by The American Thyroid Association and the American Association of Clinical Endocrinologists. As mentioned, both groups receive extensive funding from Abbott Labs, manufacturer of Synthroid, and Synthroid is the product referred to frequently in this release as "the most widely prescribed brand of levothyroxine." Synthroid is concerned with declining market share, given that it has enjoyed a near monopoly market domination for levothyroxine, and has consistently charged substantially more than its competitors. Patients and insurers will rightly be interested in the possibility of switching to lower-cost products, if they can be used safely instead of Synthroid. Keep in mind that while being on a generic drug opens up an area of concern -- you can get a different maker's generic each time you refill -- you can switch to another brand name of levothyroxine (Levoxyl, Levothroid and Unithroid are all available in the U.S.) which will offer brandname consistency one you are stabilized on that drug -- at lower prices than Synthroid in most cases. For example, the prices at Drugstore.com for levothyroxine 112 mcg 30 tablets:
- Generic: $9.99
- Levothroid: $9.99
- Levoxyl: $12.99
- Synthroid: $14.99
SO WHAT DOES THIS REALLY MEAN FOR PATIENTS?
See my recent article The Generics are Coming for a look at what the concerns regarding the generics really mean for you as a patient, and what you should do.
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