Does thyroxine cause lightheadness?

[Cheryl25]

Keep feeling lightheaded.Can thyroxine make you feel dizzy?

[startagaingirl]

Hi and welcome to the forum. In answer to your question, no the hormone doesn't - it is just a direct replacement for what your own thyroid isn't making, it is not a drug. But what can cause lightheadedness is adrenal fatigue which can be an outcome of under-medicated hypothyroid. If you don't have enough of the thyroid hormones your adrenals will try to compensate by driving your body with first excess cortisol and then, when they can't produce enough of that, they will add in adrenaline. They are not designed to do this and end up becoming tired. At that point they may not be able to produce enough to cause, for instance, the increase in blood pressure required to allow you to stand up from sitting without becoming lightheaded. There are also other issues typically associated with hypothyroid such as low ferritin - a protein required to use iron properly in your blood - which can also cause this.

Do you have any recent blood test results you can share with us so that we can give you proper advice? If you are in UK you are entitled to copies of these, ask your GPs receptionist. Make sure to also get the ranges, for instance TSH 4.3 (0.5-4.2). The numbers you are looking for are for TSH, FT4, FT3, vit D, vit B12, folate, ferritin, TpoAb and TgAb. You are unlikely to get all of these as the NHS rarely tests them all. Private testing is available at reasonable cost through Blue Horizon or Medichecks.

Our parent website thyroiduk.org is a good place to start to understand what is going on as well as links to testing options and why all those are important.

There are lots of very knowledgeable people here - indeed many with a lot more knowledge than a typical GP or even endocrinologist - so please ask away with any questions.

Gillian

[Cheryl25 in reply to startagaingirl]

Gillian, I live in a suburb of Bendigo, Victoria, Australia! But, thanks for replying. You have given me lots of ideas about how to relieve the problem!

[beaton]

I can't take Levo for that reason Cheryl. For ten years I have had to argue the point.Can't stand in the shower or walk in a straight line. Last endo. said take it at night, biggest hangover ever. I'm fine on T3 only and GP has finally agreed with me. x

[caledoniancat]

Re: "adrenal fatigue which can be an outcome of under-medicated hypothyroid", however also very worth noting that being hypothyroid can be secondary to adrenal insufficiency and as you body begins to 'rev up' with your thyroid working better it also means that what ever little cortisol you have is cleared more quickly from your system. So if you have undiagnosed adrenal insufficiency i.e. Addison's disease the levo can make you feel lightheaded, dizzy especially on standing, cause vomiting, aching joints etc. Worth keeping this in mind. It happened to my teenage daughter who was first diagnosed as being hypothyroid and with levo became very ill within a few weeks. Once the underlying Addison's was discovered and medicated she was able to come off levo because her thyroid functioned well enough.

The NICE guidance states, "Have adverse effects from levothyroxine (LT4) treatment.:

Consider undiagnosed Addison’s disease if the person feels worse after starting treatment. For more information, see the CKS topic on Addison’s disease."

[Cheryl25 in reply to caledoniancat]

I don't have a thyroid.They took it out in 2002.I am on lifelong medication

(thyroxine).

[startagaingirl in reply to Cheryl25]

Well in that case you may well be in need of some t3 added to your levo, or maybe consider ndt? Many without a thyroid find they need more than levo. But it could also be that you are undermedicated. To have a reasonable chance of feeling well your ft3 should be close to the top of the range. You haven't given any results so I can't judge that. It is also important that vit d, vit b12, folate and ferritin are at fairly high optimum levels, not just in range. I am not familiar with testing options in Aus, sorry.

Good luck

Gillian

[Cheryl25 in reply to caledoniancat]

I don't have a throid anymore. A groitre kept growing and pushing my windpipe aside, so had to have it out. Now I am on thyroxine for the rest of my life.But,still get symptoms I had before.