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Thyroid UK
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Changing brand/make of levothyroxin!

wow. - its like I'm taking an entirely differnt medication, yet they are all levothyroxin; have just moved to Mercuary pharma, from a mix of workhardt and acuvist (think they've called) brands, and the differnce is amazing; no muscle cramp, pain, or weakness, no heart palpitations, no brain fog, and no fatigue, and this before the dose gets increased to nearer what it should be; currently on 50 McG a day, having secondary hypothyroiditus, from panhypopituitarism due to a TBI. - I'm next looking in to switching brand/make on the prednisolone I take for the secondary addisons, from the panhypopituitarism. just really to post this here, to highlight what an amazing differnce in my quality of life, just as a result of speaking to my pharamicist (of course the endocrine Drs and nurses at hospital were no help, and the Dr at the GP sugery just pointed me towards the pharmacist.). there is hope..

12 Replies

Huge thanks for this post. I'm also contemplating changing brand.

Did you just ask pharmacist for a different brand, or is it more complicated, eg to I need to ask doc for something different on pescription?



Ask your pharmacist. Your prescription says Levothyroxine. You can ask for Mercury Pharma 25/50/100mcg, Actavis (aka Almus) 50/100mcg, and Wockhardt 25mcg. If your pharmacist is unwilling, ask for your prescription back and take it to another pharmacy.

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OK, so I went looked at the actual manifacturers, so it might be more helpful! -Levothyroxin, The 25 McG, levo was Wockhardt, and the 50 McG levothyroxin was Actavis.

I get the impression no two people will respond to differnt brands/makes the same, but, for me;

On 75 McG levo (so one 25 and one 50 McG tab a day, I.E., both brands), I had chronic diarrhea; 6 or 7 times a day.

I fully stopped taking the medacine, as my endocrine hospital staff would do nothing; this sprang them into actually starting to pay attention to my levels, but no advice or anything re the side effects I was getting; I dropped down to 25 McG, and the diarrhea returned, but not so bad. I then dropped taking the Wockhardt 25 McG, adn instead took my 50 McG Actavis, and felt an aweful lot better, but still not right.

now I'm on the 50 McG (2 X 25 McG tabs at the moment as I'm waiting on the 50 McG to arrive), Mercuary pharma tablets; then the brain fog vanished, the fatigue vanished, my legs started working again and all the muscle pain and heart palpitations have stopped.

I'm guessing my situation is complicated, as I have panhypopituitarism; in addition to the thyroid meds, I take prednisolone steroid every day, for my adrenalism, and also have testosterone IM injections every 8 weeks; additionally I need to start growth hormone injections soon, but can't until my thyroid levels get higher.

IN terms of changing I spoke to my Dr (basically given up all hope of being talked too and treated as a human by the hospital now), and she said speak to the pharmacist; the pharmacist couldn't have been more helpful; "I will sort this"! - and she bluddy well did!- first medical profesional to ever do anything to help me when it comes to hormones.

- In addition to the panhypopitutiarsm I'm blind from a road traffic accident when I was 17, and am now in remission having had Hodgkin's lymphoma cancer last year, and also last year, having a random (second) brain hemoridge, that no one has ever even followed up. - last year when the hydrocortisone made me suicidal the Drs wouldn't do anything, until I stopped taking the medication, to force myself into an adrenal crissis, and nearly died; then at least the Drs in endocrinology acted, and switched me from the rat poisen hydrocortisone, to the prednisilone.

All is not perfect; off to GP this afternoon to follow up latest ECG that is showing my heart failing due to the steroids; which the endocrine Drs and nurses keep ignoring. - This isn't any longer a battle with the illness/disease, its a battle to the death between me and my Drs, they've one more chance in NOvember to be helpful at the hospital, before I shall have to kill them before their mistreatment and non treatment kills me.

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You have another sorry story and I hope someone can sort out your health issues.



I think it is the different fillers in brands which determine whether or not we tolerate the meds. Mercury Pharma made the palpitations I experienced much worse and I switched to Wockhardt and Actavis on which I'm fine.

I hope your symptoms improve on Prednisilone and your heart is properly monitored.


That simple - huge thanks.



This link underlines that different brands of thyroxine work in different ways & that they are not interchangeable.

Like you I greatly prefer Mercury Pharma. Others on here find the reverse is true. We are all different.

At least some medics are beginning to realise that we need to stick to same brand.


Very true in that we all respond differently, i found Mercury pharma made me feel dreadful i now take Wockhardt and seem to do okay on that.



Interesting ,as I have not had Mercury Pharma for 9months and thought it was in short supply or costlier than he rest.Or maybe being punished for profiteerng on T3. Luckily ,I seem no different whatever I get.


I used to take mercury pharma but got terrible stomach problems on it,,


A few years ago the chemist kept switching me between brands and every time I was given Wockhardt I would become ill, recovering when I was back on any other brand. When I mentioned it to three different chemists they all said that this was a known phenomenon but no one knows why, but unless a brand is specified on the prescription they are only allowed to dispense what their wholeseller has supplied. When I told my (ex) GP he told me I was talking rubbish, but I wouldn't leave his surgery until he wrote a prescription specifying a brand (I asked for one specifying Not Wockhardt but he wouldn't do that). When I recovered he "tried an experiment" and stopped prescribing it completely, told me I was cured and didn't need it again. I then spent four years getting worse and worse to the point I could barely walk and thought I may die I was in so much pain.

My sister in law is a nurse and has told me that they are taught that when patients come into hospital there are three types of medication they must keep to the same brand, thyroid related meds being one of them.

When I told my (ex) GP I'd seen on this forum that time of day made a difference to blood tests he told me I was talking rubbish. I have since found out that my mother has been reminded by her various GPs for 40+ years that her annual blood test needs to be fasting and first thing in the morning to be accurate.

When I changed GP and mentioned this he knew about changing brands having an impact, but was unaware time of day made a difference. I'd just had an early afternoon test (4.5 TSH) and ordered an early morning test (9.5 just a week later). He thanked me and said he'd learned something new and would keep it in mind for future patients. When I developed double vision he sent me to the optician's, who sent me back saying it was my thyroid. The (new) GP then put me back on thyroxine (I'd only been at the practise for a fortnight at this time) and when the double vision went away after just two days, and the other symptoms started to improve in less than a week, he also thanked me as he wasn't aware the eyes could be affected by the thyroid, he'd learned something new and would keep it in mind for future patients.

Just goes to show how some doctors are willing to learn, others aren't.


This is all so interesting. I kept getting various brands and I just felt it wasn't right for me so I insisted on Teva as I read somewhere their fillers don't include lactose. Just started them together and will see how I get on. I'm on 125 of Levothroxine. I had numerous blood tests done all on middle range. GP was going to up dose but I didn't want this.


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