Thyroid Organizations Take On Generic Levothyroxine

Should You Be Concerned About Taking Generic Thyroid Drugs?

A consortium of three organizations involved in thyroid treatment -- the American Association of Clinical Endocrinologists (AACE), American Thyroid Association (ATA) and The Endocrine Society -- have surveyed thyroid experts, and found that among their members, many doctors believe the current FDA standards for levothyroxine bioequivalence and substitution may lead to negative health effects in some patients.

Levothyroxine, a synthetic form of the thyroid hormone T4, is the primary treatment for the underactive thyroid condition known as hypothyroidism. It's currently estimated that as many as 13 million Americans take thyroid hormone replacement medication for hypothyroidism. At present, there are eight different brand name and generic levothyroxine products being manufactured in the U.S. The brand names include Synthroid, Levoxyl, Levothroid and Unithroid.

For insurance companies and HMOs, generic levothyroxine is considered equivalent to the brand names. And because there is a substantial cost differential between generic levothyroxine and many of the brand name products, insurers, HMOs and patients have been turning to generic levothyroxine.

According to the professional organizations, however, "generic levothyroxine preparations are frequently dispensed as equivalent to branded preparations, while not necessarily being shown to be therapeutically equivalent...FDA bioequivalence standards for levothyroxine product comparisons and directions to pharmacists for product substitution may result in some patients no longer receiving the proper amount of levothyroxine."

Representatives of AACE, ATA and the Endocrine Society are sharing their concerns at a joint meeting of the FDA Metabolic Drugs Advisory Committee and the Advisory Committee for Pharmaceutical Science on October 4, 2006. The consortium has three main concerns.

1. They believe that the method used by the FDA to compare the different levothyroxine products -- and which has identified them as equivalent -- is not sensitive enough to be accurate
2. The current policy generates additional cost and inconvenience, because patients require additional blood tests and dose adjustments after switching to generic levothyroxine preparations
3. The FDA is not using the serum Thyroid Stimulating Hormone (TSH) test to compare bioequivalence of levothyroxine preparations, and the consortium believes the TSH test to be "the most reliable indicator of thyroid hormone action"

The consortium claims that the different levothyroxine formulations are being substituted for one another "with little regard to whether or not they are equivalent, even by FDA, as opposed to professional society, standards." They report that:

...of the 56 potential switches between products, only 14 (25%) of these potential changes have been directly compared by bioequivalence testing. Yet, the FDA has directed pharmaceutical companies to delete the "black box" warning indicating that dose adjustments may be required after switching patients from one preparation to another—leaving patients and physicians unaware of whether or not thyroid hormone levels have been affected by the change.

What Does This All Mean?

The basic issue is that levothyroxine does vary in terms of potency from manufacturer to manufacturer.

As a patient, if you use a particular brand of levothyroxine, most batches will have a consistent potency -- barring any unusual manufacturing irregularities. So if you are on a brand name levothyroxine, and you get the same brand with each prescription refill, you should not experience much potency variation, if any.

Each manufacturer's generic levothyroxine product is also considered consistent in potency. However, when you are prescribed a generic product, your doctor is not able to specify which manufacturer's generic product you will get. And your pharmacist cannot guarantee that you'll get your generic levothyroxine from a particular manufacturer. Patients who take generic levothyroxine can, with each prescription refill, receive product from any one of the various manufacturers of generic levothyroxine. Since generic levothyroxine drugs do not have consistent potency from one manufacturer to the next, this introduces the possibility that with each new refill of medication, you will get a batch from a different that is too potent, or not potent enough -- effectively delivering too much or not enough levothyroxine.

If you get too much levothyroxine than you need, you can experience debilitating and sometimes dangerous symptoms of hyperthyroidism, for example insomnia, anxiety, high heart rate, high blood pressure, diarrhea, hair loss, and an increased risk of osteoporosis. If you get too little levothyroxine, your hypothyroidism is undertreated, leaving you with symptoms that may include exhaustion, weight gain, depression, infertility, and an increased risk of heart disease, among others.

Getting the correct dose of medication is especially critical for people who have had thyroid cancer, and pregnant women. Thyroid cancer survivors are prescribed higher doses of thyroid medication to suppress thyroid function and prevent cancer recurrence. If the potency of medication is inadequate, patients may face an increased risk of cancer recurrence. Pregnancy puts tremendous demands on the maternal thyroid function.

Insufficient levels of thyroid hormone replacement increase the risk of miscarriage, premature birth, stillbirth, and cognitive and developmental delays in the developing baby.

This is why many physicians strongly recommend that their thyroid patients take only a brand name levothyroxine, and will even mark "Dispense as Written (DAW)" or check "no substitutions" on a brand-name levothyroxine prescription to ensure that generics are not dispensed.

But if many doctors believe that generics don't offer consistent potency from batch to batch, and there are known health implications of inconsistent levothyroxine potency, then why is there a controversy?

The issue, as often in medicine, comes down to money.

Millions of Americans are in HMOs and insurance programs where cost-saving measures mandate use of generic drugs in almost all circumstances. Various generic levothyroxine drugs began to receive FDA approval in since 2001, and since that time, many thyroid patients have had no choice but to take the generic levothyroxine.

To understand the cost implications, consider these numbers. As of October 2006, the cost for a typical three-month supply of levothyroxine -- 90 pills of 88 mcg Synthroid -- is $41.99 at The same quantity and dosage of generic levothyroxine is $23.63. Over a year, this cost difference represents a nearly $75 savings per year.

Considering that an estimated 13 million people are taking thyroid hormone replacement drugs, this $75 a year represents a cost differential of $975 million for insurers, HMOs and patients paying out-of-pocket for their medications.

The consortium resists the idea that generics generate cost savings, however. Leonard Wartofsky, MD, MACP, the President of The Endocrine Society, points out that "although it has been suggested that switching patients to less expensive brands or generic formulations of levothyroxine could result in cost savings, such savings can be outweighed by costs associated with adverse effects and additional physician visits to measure TSH and retitrate dosage."

The consortium also takes issue with the methodology used by the FDA to establish that the generic and brand names are bioequivalent is flawed. They would like the FDA to use Thyroid Stimulating Hormone (TSH) to establish effectiveness and bioequivalence.

The Unspoken Issue

One issue that the consortium does not mention, however, which raises questions about the extent of their argument, is the financial relationship between these three organizations and the top-selling levothyroxine drug, Synthroid.

Synthroid's current manufacturer, Abbott Labs, and its former manufacturers, Knoll/BASF and Boots, have been financial supporters of the three thyroid-related organizations. As one of the top five selling drugs in America, Synthroid has had a close relationship with all three organizations, providing financial support for their annual meetings, advertising in their journals, reimbursing speakers and paying honorarium for sponsored presentations at medical meetings around the country, hosting and paying for lunches, cocktail parties and various events on behalf of these organizations, and funding research projects and grants for many of the organizations' leaders. The manufacturer also provides free drug samples -- as well as merchandise including patient literature, office supplies, educational posters, etc., -- to many member doctors' offices.

So these organizations rely on the financial support of Synthroid's manufacturer for many research, operational, educational and organizational activities.

At the same time, Synthroid is feeling the heat from the availability -- and lower cost -- of the generic levothyroxine. According to, 30,695,000 prescriptions for Synthroid were dispensed in 2005. And in 2005, for the first time, generic levothyroxine prescriptions outpaced Synthroid, with 32,465,000 prescriptions. (The nearest brand name prescribed was Levoxyl, with only 12,772,000 prescriptions in 2005.) The shift to generic is clearly coming mainly from Synthroid's market share, because in 2004, 44,056,176 prescriptions for Synthroid were written. In one year, Synthroid lost in business a total number of prescriptions equal to the total its closest competitor dispenses in a year. Clearly, if the FDA maintains its current equivalence standards, Synthroid's market share will continue to erode.

The question remains: Are these groups concerned that these dramatically reduced sales for Synthroid will translate into reduced financial support for their organizations -- organizations that rely heavily on funding from drug companies? Is Synthroid putting behind the scenes pressure on the groups that benefit from its financial support? How much of the argument is legitimately scientific, and how much of it is market-driven?

Another question...why does Synthroid continue to price itself so high, as compared to its competitors? As noted earlier, here are costs at for a 3 month, 88 mcg supply of levothyroxine:

  • Synthroid,$41.99
  • Levoxyl, $23.97
  • Generic, $23.63
  • Levothroid, $23.05

Yet, a survey of Canadian mail order pharmacies shows that the price for a 90 pill supply of Synthroid, 88 mcg, is approximately $21 to $24 US. Some industry analysts have suggested that Canadian retail drug prices are more representative of a fair retail price for American drugs, suggesting that the high markup on Synthroid may be motivated by profit.

In the case of Synthroid, for example, a Congressional investigation found that the monthly retail cost to seniors was $27.05 -- which was 1,446 percent more than the $1.75 paid by favored group purchasers at the time of the investigation. The question that this raises, is, if Synthroid can afford to charge bulk purchasers only a few dollars a month and still remain profitable, what is the actual manufacturing cost to the company, and why is it necessary to charge consumers as much as $40 or more per month for Synthroid?

What Should You Do?

The main question for you, of course, is: What should you do?

  • First, keep in mind that consistency is key. If you are taking the same brand name of levothyroxine on a regular basis, this issue really should not affect you.
  • Check your prescriptions when you pick them up. You may not always know when your HMO, insurance company, or even pharmacy, will substitute a generic for a brand name. Don't assume that you're continuing to get a brand name levothyroxine without confirming it, each time you get your prescription refilled.
  • If you do not want the pharmacy to switch you to a generic without discussing it with you, be sure that you have your doctor write "Dispense as Written" (DAW) or "No substitution" on your prescription slip. Note, however, that your HMO or insurer may only cover the cost of generic drugs, and refuse to reimburse you for brand name drugs.
  • If your HMO or insurer refuses to cover a brand name levothyroxine, consider talking to the company's consumer representative or ombudsman to see if this can be negotiated, or have your doctor write a letter regarding your medical need for a brand name medication.
  • Keep in mind that the copay for your medication, often $10 or $20 per prescription, may be close to the cost of medication. Rather than fight with your insurer, you may want to simply pay for a lower-cost brand name, like Levoxyl -- out of pocket.
  • If you are pregnant, or have had thyroid cancer, talk to your physician, but you probably will not want to accept generic levothyroxine. Even if you have to pay out-of-pocket for your medication, consistent thyroid medication is essential. Regarding reimbursement, your doctor may be able to argue with your insurer or HMO that your health requires a brand name medication.
  • If you want to switch from a more costly brand, i.e., Synthroid, to a lower-cost brand, plan to have your thyroid retested after about six to eight weeks, to make sure that the dosage of the new drug is correct for you.
  • If you must stay on a generic, talk to your pharmacist. It may be possible to informally ask the pharmacist to get a particular generic brand. There are no guarantees, but a good relationship with the pharmacist can often go a long way.

And, in my opinion, don't forget to contact the various groups that represent thyroid patients and professionals, and tell them as a thyroid patient, you want your interests represented. Personally, I think it means wanting not only a policy that puts patients -- and not insurers and HMOs -- first when it comes to generic vs. brand name levothyroxine, but one that does not favor Synthroid or another drug. Especially when a brand is substantially more costly, without conferring any particular scientific benefit for that extra cost, as compared to its competitors.

Ultimately, the concerns of these groups -- and patients -- could be dramatically reduced if Synthroid brought its costs in line with its competitors, or if HMOs and insurers could specify that patients get the lower-cost brand name levothyroxine drugs, like Levoxl, Levothroid or Unithroid.


American Association of Clinical Endocrinologists press release, October 2, 2006, Online
RxList, The Top 300 Prescriptions for 2004 by Number of US Prescriptions Dispensed,
RxList, The Top 300 Prescriptions for 2005 by Number of US Prescriptions Dispensed.
Survey of Canadian mail order pharmacies:,, October 3, 2006
Shomon, Mary. "Lawsuit Stalled, Congress Tackles Overpricing, Research Says It May Not Be Enough," website, 02/28/99 Online

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