Background
The current Teva levothyroxine in the UK was introduced as a brand new formulation around 2016. (There was no Teva levothyroxine product for a few years - approximately 2012 to 2016.)
Teva introduced 12.5, 25, 50, 75 and 100 microgram dosages. These were the first 12.5 and 75 levothyroxine dosages ever in the UK. Potentially very convenient.
Reports
As the number of people getting Teva levothyroxine increased, we saw a number of reports from individuals which identified they felt unwell when they took Teva levothyroxine - issues which did not occur with other makes.
Slowly, after people had swapped makes, and maybe tried Teva more than once, it started to look like there was a problem for some people with Teva levothyroxine.
However, alongside these reports, others were saying how Teva was the best levothyroxine they had ever taken.
Explanations
1️⃣ First, Teva was the only lactose-free levothyroxine tablets in the UK. Therefore, anyone with problems tolerating lactose might well find it better for this reason. (Since then Aristo Vencamil and - though availability is a major issue - Glenmark have been released. Both of which are lactose-free.)
2️⃣ Second, Teva’s only unique excipient is mannitol (E421) so it is natural to suspect that could be a cause.
This suspicion had some backing from issues which occurred with Merck’s levothyroxine when the formulation of that changed - first in France, then around the world. The new formulation more or less swapped the lactose out and replaced it by mannitol. And there were reports from several countries of issues some of which were similar to the UK Teva issues.
3️⃣ Third, Teva levothyroxine, along with Advanz/Mercury Pharma levothyroxine (including UK Eltroxin) contains acacia. Despite research into acacia finding few issues, this has long been suspected to be a problem excipient for some people.
4️⃣ Fourth is “anything else”. There might be factors including some which we would never suspect.
What do do?
▶️ Always check the product you have been dispensed - while still at the counter in the pharmacy. This is plain sensible advice for all medicines.
▶️ If you find Teva levothyroxine and have found it fine in the past, then you should still be fine. Indeed, you might find it the best formulation available for you.
▶️ If you find Teva and have never before tried it, accept it. When you get home, swap to Teva as soon as possible. That way, if you have a problem, you probably have some of your previous prescription to tide you over while you sort the issue out. And make a Yellow Card report.
▶️ If you find Teva and have previously had issues with it, ask the pharmacy to exchange it.
▶️ Be aware that AAH Hillcross levothyroxine - in the 25 microgram dosage ONLY - is actually Teva product. (Of course, if you get on well with Teva, be aware that the 50 and 100 microgram AAH Hillcross dosages are actually Accord product!)
▶️ Also make notes of all levothyroxine products you receive, any changes (good or bad) you associate with taking them. We all tend to think we will remember everything but, very often, we don’t.
These are all simple enough in themselves. But they can be complicated by unhelpful attitudes of prescribers and pharmacists; if you are on multiple dosages; if you are taking other medicines.
You can take other steps to ensure you do, or do not, get Teva in future. But I’m trying to limit the size of this post!
Yellow Cards
Many of us on the Thyroid UK forum repeatedly advise that anyone who has issues with any medicine to make a Yellow Card report.
🟨 Making Yellow Card Reports 🟨
https://healthunlocked.com/thyroiduk/posts/149805841/making-yellow-card-reports
Final Point
We do not know any way of identifying in advance who will, or will not, tolerate Teva levothyroxine. Only if you categorically know you have an issue with one of its excipients.
If you do not try it when you have the opportunity, you could avoid having an issue, or you could miss out on what might be the most available levothyroxine and what might possibly be the best levothyroxine for you.
This was originally posted on the HealthUnlocked forum. There are some replies which you might wish to read:
Teva versus the rest
https://healthunlocked.com/thyroiduk/posts/151370649/teva-versus-the-rest
[i][b]helvella - Teva versus the rest[/b]
A discussion of the issues surrounding Teva levothyroxine.
Last updated 10/02/2025[/i]
Link to blog:
https://helvella.blogspot.com/p/helvella-teva-versus-rest.html
If you find anything incorrect, misleading, typos, links that don’t work, etc., please let me know. Go to my profile and use the contact details there.
