Came across this article by chance and thought I’d share it.
Will caveat that the research was commissioned by the manufacturer of Synthroid so clearly a vested interest and in no way independent.
Would be intrigued if there was a similar analysis of the UK brands of Levo to compare their efficacy. We’ve all seen the discussion on these forums about side effects of each brand, but I’ve yet to see anything about efficacy especially in relation to TSH and T4 levels.
Published online 2020 Sep 30. doi: 10.1001/jamanetworkopen.2020.17645
PMCID: PMC7527873
PMID: 32997127
Comparative Effectiveness of Generic vs Brand-Name Levothyroxine in Achieving Normal Thyrotropin Levels
Juan P. Brito, MD, MSc,
1 Joseph S. Ross, MD, MHS,2,3,4 Lindsey Sangaralingham, MPH,5 Sarah K. Dutcher, PhD,6 David J. Graham, MD, MPH,6 Zhong Wang, PhD,7 Yute Wu, PhD,8 Xiaoxi Yao, PhD,5,9 Robert C. Smallridge, MD,10 Victor Bernet, MD,10 Nilay D. Shah, PhD,5,9,11 and Kasia J. Lipska, MD, MHS4,12
Question
What is the comparative effectiveness of generic vs brand-name levothyroxine in achieving normal thyrotropin levels?
Findings
In a cohort study of 17 598 patients from a national administrative claims database, a similar proportion of generic vs brand-name levothyroxine users achieved target thyrotropin levels.
Meaning
These findings suggest that initiation of generic or brand levothyroxine for mild thyroid dysfunction is associated with similar rates of achieving target laboratory outcomes.
Whether the use of generic vs brand levothyroxine affects thyrotropin levels remains unclear.
Objective
To compare the effectiveness of generic vs brand levothyroxine in achieving and maintaining normal thyrotropin levels among new users.
Design, Setting, and Participants
This retrospective, 1:1 propensity score–matched longitudinal cohort study used the OptumLabs Data Warehouse administrative claims database linked to laboratory results from commercially insured and Medicare Advantage enrollees throughout the United States. Eligible patients were adults (aged ≥18 years) with thyrotropin levels ranging from 4.5 to 19.9 mIU/L who initiated use of generic or brand-name levothyroxine from January 1, 2008, to October 1, 2017. Data were analyzed from August 13, 2018, to October 25, 2019.
Exposure
Patients received generic or brand-name levothyroxine.
Main Outcomes and Measures
Proportion of patients with normal vs markedly abnormal thyrotropin levels (<0.1 or >10 mIU/L) within 3 months and with stable thyrotropin levels within 3 months after the thyrotropin value fell into the normal range.
Results
A total of 17 598 patients were included (69.0% female; 74.0% White; mean [SD] age, 55.1 [16.0] years), of whom 15 299 filled generic and 2299 filled brand-name levothyroxine prescriptions during the study period. Among 4570 propensity score–matched patients (mean [SD] age, 50.3 [13.8] years; 3457 [75.6%] female; 3510 [76.8%] White), the proportion with normal thyrotropin levels within 3 months of filling levothyroxine prescriptions was similar for patients who received generic vs brand-name levothyroxine (1722 [75.4%; 95% CI, 71.9%-79.0%] vs 1757 [76.9%; 95% CI, 73.4%-80.6%]; P= .23), as was the proportion with markedly abnormal levels (94 [4.1%; 95% CI, 3.4%-5.0%] vs 88 [3.9%; 95% CI, 3.1%-4.7%]; P= .65). Among 1034 propensity score–matched patients who achieved a normal thyrotropin value within 3 months of initiation of levothyroxine, the proportion maintaining subsequent normal thyrotropin levels during the next 3 months was similar for patients receiving generic vs brand-name levothyroxine (427 [82.6%] vs 433 [83.8%]; P= .62).
Conclusions and Relevance
Initiation of generic vs brand-name levothyroxine formulations was associated with similar rates of normal and stable thyrotropin levels. These results suggest that generic levothyroxine as initial therapy for mild thyroid dysfunction is as effective as brand-name levothyroxine.
In my book, the Synthroid paper has many problems. Not least their decision to use a fixed TSH range despite collecting data from different labs. And that they seem to compare one make against "all others".
Also, with the near total demise of Mercury Pharma Eltroxin, we really don't have anything like the same generic vs. brand issues that are so regularly reported from the USA.
I'm not in the least convinced by the idea that there is anything special about branded products.
After all, this story appeared on 1951/10/27:
Now Under Trade Name.—Glaxo Laboratories, Ltd., Greenford, Middlesex, announce that I-thyroxine-sodium, Glaxo, is now supplied in both strengths under the trade name Eltroxin. There is no change in packs or prices.
Glaxo just invented a name and applied it - without any changes to the product - because they wanted to!
Just adding:
Glaxo (by then GlaxoSmith Kline) sold worldwide rights to Eltroxin to Aspen - and the product formulation changed and moved site of manufacture. This was a step in the multiple issues about changes to Eltroxin in several countries including New Zealand.
GSK bought an 18% interest in Aspen.
Eltroxin in India and the UK is still not owned by Aspen!
Well, it's over seventy years and I am not aware of any specific claims that Eltroxin has special qualities. And Glaxo sold on the Eltroxin brand in the UK something like thirty years ago!
Hi Dk123 I've tried both generic UK levo and Synthroid (I buy it from overseas to UK). All helped my thyroid levels the same, so technically no difference between branded and generic for me. But I can't tolerate UK generics. I can only tolerate Synthroid. UK generics gave me impossible symptoms to deal with. I tried and tested on and off the generics and Synthroid and got the same reactions every time.
It actually maddens me that we don't have brands in the UK
I read somewhere that Synthroid fixed the results of that experiment!! I don't know how true that is but that wouldn't have done them any favours really
So are you saying all the brands you tried have you the same thyroid results but you had less/no side effects on Synthroid?
It’s strange that even private patients in the UK do not get offered anything other than generic Levo. Generics are cutting every penny to increase their margin so likely they will add cheap ingredients, no different to drug dealers cutting cocaine with flour, sugar, etc!
I see this problem repeated in all medicines, human and animal!! Foods and drinks too. I end up looking like a labels snob, but my body knows best. If there's a dodgy cheap ingredient in it, then Nope, I get reactions.
But they cannot just change ingredients at the drop of a hat!
Any changes must be approved by the MHRA. If they buy an ingredient like microcrystalline cellulose, they could get it from a different supplier to save costs. But it has to be of the same official standard.
It was a failure to abide by that requirement which caused the Teva product to be removed from the market. They switched the specification of the dextrin ingredient which impacted on the effective dosing. This was absolutely against the rules.
Further the one brand we in the UK have, Eltroxin., is absolutely identical to Mercury Pharma levothyroxine (as a generic).
Totally agree they cannot change the ingredients, but even upon launch of a generic they are clearly competing on price and their formulation will be cheaper than the competitors otherwise why would you launch a generic unless you can compete on price?
The only way to be cheaper is to cut some ingredient costs or produce in a cheaper country. It’s these cheaper ingredients that lead to most of the issues people have with various drugs. Yet for some reason most doctors behave like there’s no difference between the different brands of drugs.
But Mercury Pharma supply the exact same product as both a generic and a branded product.
And, until recently, Unithroid in the USA was also supplied as Lannett, which was widely regarded as a generic brand.
Most UK products were released many, many years ago and generally have not made major changes to ingredients. They are more likely to have been shifted from one company to another. For example, Cox to Hoechst (by ownership but not branding) to Alpharma to Actavis to Teva (temporarily and not branding) to Accord (which is owned by Intas).
I'm no pharmaceutical manufacturer, but I wouldn't actually be surprised if the cost of all the ingredients of levothyroxine was less than that of the blister pack in which the product is distributed. I've looked back recently at some prices and had to pinch myself at the low cost, even allowing for change of currency value over the years, of things like 1000 tablet packs.
I think you are missing the point I’m making, doctors need to be a bit more clued up about the differences between brands (whether “branded” or generic “brands”) and make active decisions about what is the best tablet for the patient.
The fact is doctors prescribe Levo and do not entertain the possibility that each generic has different ingredients that can cause problems to different people. We already know that there’s lactose in most of the brands except Teva (from memory). Another forum member talks of acacia intolerance from certain tablets. I’ve seen 9 different Endos privately and not one has ever discussed the brand of Levo I take and whether I’m suffering from an allergy/intolerance to one of the ingredients.
I call that lack of rigour in the performance of their duties. I wouldn’t be able to get away with that in my job and neither would many other professions.
In 1951, Glaxo changed the name of their levothyroxine product to be a brand - Eltroxin.
What is the advantage of it being assigned the brand name - Eltroxin - and not "just" levothyroxine?
A prescription could be written for "levothyroxine" and, additionally, the manufacturer name, or for "Eltroxin". There is, therefore, this minor difference in prescription-writing.
What would you want to change about the selling and prescribing of levothyroxine from Wockhardt, Teva, Accord, Aristo and Mercury Pharma?
(I feel that the own brand suppliers, Almus and Northstar, actually cause more issues because they confuse so many of us.)
Almus and Northstar are not manufacturers at all. They are, officially, "own label suppliers". The product is manufactured and licenced and the responsibility of Accord and simply put into boxes saying "Almus" (but also state the manufacturer name along the bottom edge).
But there is no guarantee that the products will always be supplied by Accord, or that all dosages will be from Accord.
(Northstar 25 microgram tablets are made by Teva.)
What I would like is more recognition of the differences between each brand of generic rather than them being lumped into one pot.
For doctors to understand which tablets contain what, especially the more common allergens like lactose as in my experience doctors seem oblivious. Why prescribe a tablet containing lactose when a patient is intolerant - seems like madness to me!
There needs to be some understanding of the pros and cons of each brand as currently doctors simply prescribe Levo and leave the patient at the discretion of a pharmacist who may well be in a warehouse somewhere packing drugs to be despatched to the retail pharmacy store and may never meet the patient nor understand their needs.
But at least we can see the manufacturer of each product. It is not like once was the case for some medicines that we'd get anonymous tablets from a bulk pack and be unable to identify the maker.
Not obvious I agree, but doctors should be involved in the discussion of which brand to take, taking into account potential allergies and intolerances.
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Taking B12 with Hypothyroidism 
Zulewski score for hypothyroidism
Hypothyroidism?
New insights into hypothyroidism...
