Thyroid UK
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Levothyroxine & allergy pills

Hi all,

I have had a tired week. I am on 75ug Levothyroxine for now (early days, being reviewed every 2 months, not yet normal TSH levels). I have prickly heat rash on my hands so I took a Asda own brand allergy relief pill.

I became so tired I nearly fell asleep at my desk. My eyes were stinging and I felt like crying because I just wanted to sleep. The worst of it passed that evening but I have been tired all week since.

I asked a friend who also has Hypothyroidism and she said i should only take allergy pills with Cetirizine (sp?) in as that is what the Dr prescribes her because it is less likely to cause drowsiness or react with the LevoThyroxine.

When I checked, that is what I had taken!


So I have not taken any more but the prickly heat is so bad I need to take something or I am going to scratch my hand off!

I will see my GP on the 15th July but may not have any skin left by then, or indeed my job if I fall asleep at work!

10 Replies

Maybe have a look here:

They suggest, among other things, a low-dose hydrocortisone cream (which is available over the counter).

If you are looking for a standard anti-histamine, I quite frequently take Loratadine and am not aware of any interactions on the thyroid front. It too is non-drowsy.



I take Loratadine along with 75/100 mcg levo and 40 mcg carbimazole too and no problems. Hope you get sorted out soon.

Liz x


That's a great artical, thank you. I will going to the pharmacy today to try the cream. Interestingly enough it says the prickly heat could also be causing the exhaustion!!


Why Levo and carbimazole Liz?


The hospital I attends useswhat is known as 'block and replace' They give you Carbimazole for a while, in my case I had 20 mcg from the end of December until early January then a blood test and they raised the dose ( consultation by letter :-) ) to 40 mcg until I got to see the endo at the end of February when I was then given levo, by that time I had gone from being really hyper to being hypo.

The guy I saw explained all the different options there are for treating Graves, he started with TT, then RAI, then finally got to using drugs to treat it and explained about titration where they just give carbimazole and about block and replace where they kill everything off and then give you T4, then he said that his hospital goes for the fast method which was B&R and said that I would be with them for two years - didn't seem very fast to me.

So, he said to stop the carb for 'a few days' ????? and gave me a prescription for 50 mcg levo that I had to start immediately then after the 'few days' I was to take both drugs. I have had two increases 50 to 75 and now I'm taking 100 and 75 on alternate days. I read somewhere that B&R and the titration method where you keep reducing your Carbimazole as you go along both give the same end result but that you needed more frequent blood testing if you were using Carbimazole alone and that the end result was the same so I don't know why specialists chose one method over the other.

Do you know that you can get antihistamine cream that you can rub on - the sort of stuff you get for insect bites etc so it might be worth trying that also my husband has eczema and when his hands were really itchy he used to hold them under a cold tap - well he used to rub ( scratch?) them under a cold tap. He sometimes used a mild hydro- cortisone cream too but it can thin your skin and he tended to keep that as a last resort.



Sorry, end of November to January.



Wow, that all seems very complicated, I guess he knows what he is on about! Mine seems very simple at the mo, TSH isn't normal take LevoT, still not normal, take more LevoT etc.

What is this link with Hypothyroidism and carbs? Funny enough I initially went to the Dr thinking I had Coeliacs but that test was negative but showed my high TSH levels.

I am going to the pharmacy a bit later when it isn't so hot out so will ask pharmacist about the antihistimine creams and hydrocortisone etc.

Many thanks :)


Cetirizine can cause drowsiness in some people better off with loratadine


I regularly take loratadine antihistamines and haven't had any problems with taking with 100mcg of levo - sounds like you may simply need to chamge from cetrizine to loratadine - hope this helps x


I might try Piriton then (Loratadine), the hydro cortisol stings!

Thanks all.


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