Tuesday, June 25, 2013

Do You REALLY Need Brand Synthroid?

You people are out there... spending $20 to $30 on brand Synthroid month after month: You're throwing your money away. It's your money to throw away, but you really don't need to do that! 

First a little history...

In 1986, Flint Laboratories, the then-manufacturer of Synthroid, contracted with a researcher at the University of California to conduct a study that they hoped would demonstrate that Synthroid was a better product than the major competitors' products. Unfortunately, when the study was completed in 1990, it clearly showed that all available brands of levothyroxine were, in fact, equal. 

In the intervening years, Flint Laboratories was sold to Boots Pharmaceuticals. When the researchers attempted to publish their results, Boots Pharmaceuticals exercised a clause in the contract that required their approval of the publication. The publication of the results of the study would have theoretically resulted in a switch to less expensive competitor products and a potential loss of the near monopoly Boots had on the thyroid replacement market. Boots Pharmaceuticals was sold to Knoll. Knoll persisted in their opposition to the publication of the study. 

Intervention on the part of the FDA finally broke the impasse. The manuscript was eventually published in 1997 in the Journal of the American Medical Association. With the publication came more than 60 class action suits alleging consumers had paid 2-3 times what they should have paid for levothyroxine as a result of the suppression of the University of California study from 1990 to 1997. Knoll eventually settled the case for $135 million.  LINK

So basically, the study says the generic IS just as effective as the brand.

Just recently, though, some researchers contend that it may be better to just switch to a natural thyroid product:

New Study Shows Natural Thyroid Better than Synthetic

Comparing Synthroid to Natural Thyroid: Their controlled study compared natural thyroid with Synthroid. What they found was that roughly half of the patients (48%) felt better on the natural thyroid, one-third had no preference, and one-fifth (18.6%) felt better on the Synthroid. Clearly the natural thyroid wins the comparison test (48.6% vs. 18.6%).

"At the end of the study, 34 patients (48.6%) preferred Desiccated (Natural Thyroid), 13 (18.6%) preferred Levothyroxine (T4), and 23 (32.9%) had no preference". LINK 

And yet, here's an ALTERNATIVE OPTION: 
All you really need to do is adjust the dose

Suppose for example, my high maintenance patient (let's call her Amy) has an open prescription for 88 mcg of Synthroid. Like a lot of my Goofmart Pharmacy patients, she insists on having brand Synthroid (despite the checkered past of the manufacturer). Amy's doctor wants to make her happy, so he prescribes it DISPENSE AS WRITTEN: Synthroid 88 mcg.

In case you didn't know, all the of the thyroid products come in different strengths. That's because thyroid medication has a "narrow therapeutic index." But what is a narrow therapeutic index?

A narrow Therapeutic Index is defined medically as the ratio between the average effective dose and the average lethal dose. It is an extremely close margin between an effective concentration of a therapeutic drug circulating in the blood and a fatal concentration. LINK

So a drug with a narrow therapeutic index has to be dosed carefully because it can go from being therapeutic to toxic very quickly depending on the patient and his/her needs.

In the past, patient Amy went to her doctor with symptoms of hypothyroidism. Her doctor ordered labs and the results indicated her thyroid function was low and suggested her getting a boost with thyroid medication. So the doctor put her on 88 mcg of Synthroid (based on her labs) and had her back in another 4-6 weeks to check the labs again. It's trial and error... with the error being on the low side of optimal to prevent toxicity. Doctors always start low and gradually increase... better to give too little than too much. We want therapeutic, not toxic.

But does Amy really need to have BRAND Synthroid? Given the history of trouble with the company, is that warranted? Given the suppressed study which shows that the generic is just as effective as the brand, why pay more? Given that the recent study of natural thyroid replacement (or as we call it in the pharmacy.. pig-throid) suggests the natural replacement is more effective, is brand (or generic) still warranted? That's something Amy needs to talk over with her doctor and her kitties.

And yet there is still a another option

Until there are more follow-up studies on natural (pig-throid) versus synthetic levothyroxine (brand Synthroid or generic levothyroxine), there will be those who insist on having BRAND Synthroid and doctors who will continue to prescribe it for them. But... really... is brand medically necessary?

Let's suppose that generic levothyroxine is not as potent as the brand Synthroid. That's not really true, but there's a lot of people who swear by it. Some people think the excipients affect absorption. Other people think the generic is less potent. I've heard all the stories.

Ok... let's pretend it is true... now what?

So let's say, for this example, that generic levothyroxine labeled as "100 mcg" is "therapeutically equivalent" to "88 mcg" of "the real stuff" -- brand Synthroid. (Let's further avoid the philosophical debate as to how a synthetic thyroid product, i.e. SYNTHroid manages to get called "the real stuff" -- that's another blog post entirely). 

Therefore, if 100 mcg of generic levothyroxine is equivalent to 88 mcg of Synthroid:


Run the labs! If the patient does well on 100 mcg of generic levothyroxine there would be no need to prescribe brand! Instead of focusing on brand versus generic, the prescriber should be concerned with how the patient is doing. TREAT THE PATIENT, NOT THE NUMBERS YOU WEASEL. It doesn't matter if the patient is on brand or generic if you're talking about potency. All that is needed is an adjustment in dose based on the labs of the patient. Meow, meow, meow!


Anonymous said...

Thanks for the post. I take generic levothyroxine, and usually feel things are pretty good. Then I occasionally read some of those (admittedly not researched) things about how the generic thyroid meds aren't as good, and confess to some uneasiness. I should do more research from objective sources, but some of them are a little hard for me to comprehend - so I appreciated the clear language here! I think I will be sticking with the levothyroxine. I don't know what the Synthroid would cost with my insurance, but I will bet it won't be the 0.80 a month I pay for my levothyroxine.

Anonymous said...

You didn't comment on the overwhelmingly most common reason doctors write for name brand synthroid instead of generic(based on my personal experience as a thyroid pt, discussions with endocrinologists, and my own practice as a physician).
Generics are required to be bioequivalent to the name brand. Bioequivalence, per the FDA, means they deliver 80-125% of the same dose as the namebrand.
The range of bioequivalence of a 100mcg levothyroxine than means the actual delivered dose for a particular generic could be anywhere from 80mcg to 125mcg. Since there is a 88mcg, 100mcg, 112mcg, and 125mcg dose available that means this generic could be anyone of 4 different doses.
So this month I take generic A 100mcg levothyroxine and actually get 88mcg. Next month, I get generic B 100mcg levothyroxine and actually get 125mcg.
For Diovan, being in the range of 32-50mg for the 40mg dose does not make a significant clinical difference.
For levothyroxine, 88 vs 125mcg can make a huge clinical difference.
So yes, I will be the doctor and treat my patient appropriately. So when their subjective feelings and their objective labs are all over the place on generic levothryoxine, than I change them to namebrand Synthroid or Levoxyl.


pharmaciststeve said...

IMO.. if the pt gets the same manufacturer of the generic each time.. there should be little/no variation.. this is where the brand name drugs have a "edge" .. especially with NTI meds. The lab ranges of free T4/T3 is quite broad and there is a school of thought that a number of pts - who are within range.. are actually suffering from sub clinical hypo thyroidism..
You give these pts .. some T4 and all it does is cause a reduction in TSH.. meaning that you get right back to where you were.. In these pts.. you need to have total t4 supplementation and shoot for t4 to be in the middle of the range..

Anonymous said...

To the good doc, bioequivalence is defined as having the 90% confidence interval of the true mean of the ratios of Cmax and AUC fall 80-125% of the reference product. In referencing your 100 mcg dose of levothyroxine. If your true mean was close to 80 or 125 mcg, they would not meet the criteria of 90% confidence interval. The actual difference is probably in the 3-5% range. Granted, levothyroxine is still a narrow therapeutic index drug and the pt should be properly monitored. Millions of people take generic levothyroxine without incident. Hopefully, people use the same pharmacy and the pharmacy consistantly dispenses the same manufacturer. I take generic levothyroxine 88 mcg and my TSH within therapeutic range. It took my doc several dose adjustments to get me there, but it would have with Synthroid, too. Also, there can bioavailability variances within batches of Synthroid (or any drug for that matter). As you stated, if you have huge variablity with some pts on generic, a switch to brand would be warranted. However, I do disagree that every dose of levothyroxine should be a branded product as some endocrinologists would lead you to believe

robinsa4 said...

As stated by a previous poster, if one could be certain that the pharmacy was always stocking levothyroxine by the same manufacturer, then the scenario in your post would be fine. But since that is not the case, many people prefer to prescribe branded product in order to ensure consistency.

I'm a pharmacist who is hypothyroid. I tried going from Synthroid to generic levo. I went back to Synthroid when my hair started falling out and haven't had a problem since then.

pfongk said...

I'm on thyroxine or eutroxic which are the two brands available in Australia, I just take whatever and have never had a problem with it. On the other hand, my son has had issues with medications due to having Coeliac disease and the filler having gluten in it. I wonder if something similar might be why some people have issues with generics.

Unknown said...

Ive taken levlrhyroxine since day one. My levels have been good on generic. And im a pharmacsit, figure as long as ib ger same generic brand im good and no complInts.

Anonymous said...

I know this is old... but I was reminded of this the other day when I saw this script come in:

Synthroid 88mcg BRAND MEDICALLY NECESSARY. Sig: 1/2 tab daily

Ah, I love it. I hope their pill cutter separates that table into exactly 44mcg each. Because, you know... it's the generics fault your levels are out of whack.

Anonymous said...

I switched from levothyroxine to Armour and gained 15 pounds and couldn't stay awake. Switched back to levothyroxine and I'm losing the weight I gained. I'm a marathon runner, running 60 miles a week when I'm not training, more when I'm training, so the weight gain was horrible.

Gabriella Kadar said...

Is there generic Cytomel? Because this stuff is sinfully expensive.

Anonymous said...

So this is really old, but to the comment about 88mcg 1/2 QD it is not the daily dose being exactly the same that matters.
It has been studied that it is possibly OK to take a weeks worth of synthroid at once and that overtime there is a steady state reached(don't have link for the study at hand here) so taking 40mcg today and 48 tomorrow, over time, is OK. But taking 80mcg today and everyday instead of the intended 88mcg could make a difference.

Tom Bridgeland said...

Had a patient question me on this just two days ago. Says the generic 'hurts her bones'. I told I'd call the pharmacist to see if it was synthroid or generic, but she just took it...?

Laura Lea said...

I am a pharmacist and there is a 10 to 20% difference in ANY generic and brand. My mom can tell the difference between brand and generic Synthroid. My advice is if you start with brand name then stick with it. If you started with generic then stick with that. My mom takes generic on all other meds. Any hormones stick with Brand. It’s just my opinion. I have seen the difference in the lab values.

Laura Lea said...

I am a pharmacist and there is a 10 to 20% difference in ANY generic and brand. My mom can tell the difference between brand and generic Synthroid. My advice is if you start with brand name then stick with it. If you started with generic then stick with that. My mom takes generic on all other meds. Any hormones stick with Brand. It’s just my opinion. I have seen the difference in the lab values.