Thyroid UK
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What is the effect of GA on thyroid?

Had surgery under GA on 2 Jan. Felt ok at first, now got vertigo like i used to have before i switched to ndt. I was given a premed without my consent. I don't know if that makes the horrible side effects of GA last longer?

12 Replies

Hi BlueDaff

Not an answer sorry - just wanted to check that GA is General Anaesthetic?




Premeds are normally given to ameliorate the effects of general anesthetics, e.g. to reduce anxiety & pain, to reduce post-operative nausea etc. As far as I am aware, giving consent for surgery & anesthetic also means you give consent for pre-meds as they are part of the anesthetic & surgical procedure.

You should talk to your surgeon and/or anesthesiologist about your symptoms and ask what drugs you were given and whether or not they may be contributing to the effects you are experiencing.

I had two GAs in 2012 and I had quite a long discussion with my anesthesiologist before each surgery as I have a history of chronic pain. Being in pain all the time obviously presents quite a challenge to an anesthesiologist trying to control opertive & post-operative pain. In both instances I was given pre-medication before surgery.

All anesthesiologists & surgeons want a patient to be euthyroid before any procedure. This is not only because of the effects of anesthetic, but primarily because surgery itself is extremely stressful for the body. I was sub-clinically hyperthyroid for most of last summer. After the GA I had in September, I suddenly went HYPO (TSH of 12). I spoke to my surgeon about it and his advice was to ignore any thyroid results taken within 30 days of surgery due to the effects of surgery on the body. Since then, I have gone hyper (no more sub-clinical; T3 of 31 and now 40). So, I can no longer have GA due to the risk of "thyroid storm" due to my hyperthyroidism.

I would suggest that you speak to your consultant about the effects you are experiencing. I don't know what surgery you had, but remember that surgery in and of itself is an enormous stress on the body. My surgery in April was only about 45mins; the one I had in Sept was over 1.5 hours, about the limit they can do with a tourniquet, and my recovery in Apr was easier than my recovery in Sep. But I did not experience any vertigo.

Please speak to your consultant.


A pre-med will generally allow General Anesthesia to work more rapidly/effectively & some of the drugs used for a GA can have the kind of effect your going through for sometime afterwards. I have trouble with all Morphine based drugs commonly used in GA but if pain management during surgery/ aftercare is a consideration then the benefits probably outweigh any disadvantages.

Something else which I feel can effect Hypothyroidism & have had experiance of is the type of pain relief given afterwards.

Hope you feel better soon.


Interesting. Unfortunately i do not have access to either the anaesthetist or consultant now that surgery is over.

For the record, we specifically discussed pre meds and i specifically stated i did not want a pre med (thus did not consent) and was given one against my will.

I have a suppressed tsh-which they knew at the shambolic pre op assessment, but no one said anything about my thyroid on the day.

As always , this forum is far more helpful than any of those one would expect to receive advice from (eg anaesthetist, surgeon)


After surgery, I experienced fainting and weakness when I tried to get up, when back on the ward, which was very distressing . The doctor was called and he said that people with hypothyroidism are known to experience these symptoms and perhaps i was allergic to the morphine. I was not allowed a pre med and i am surprised that you were given one, as they don't tend to give them these days.

I do hope you are feeling better soon, as through my experience, recovery may be slower with hypothyroidism.


Interesting comment re: pre-meds. I have had a pre-med at each of my GAs (I have had 6 over the past 10 years). Maybe it is dependent on what sort of surgery you are having as most of mine have been orthopedic.


We have a lot in common. I have had 6 orthopaedic ops over the last eight years, including a knee replacement.I have found this has stressed my body a lot.They do not believe in giving pre-meds at Guys-something to do with them hindering your recovery. Personally I prefer a pre-med, because I get so nervous before ops.

I am due to have a second knee replacement, but I need to have all my post-op issues sorted out before I go through all that again.


That's odd re: the pre-med. Do you remember what they wanted to give you (that you objected to) or, indeed, what you were in fact given? That might help work out if it is contributing to your vertigo.

I would still try writing to the consultant - I write to my various consultants all the time (saves dealing with snarky medical secretaries who think they are God's gift). The consultant or anesthesiologist would be in the best position to evaluate if your symptom is related to anesthetic or pre-medications.


This is very helpful, thanks everyone


I was of course not told what i was given, so will write.


Hi Just to say that I am hypo and had vertigo after general anaesthetic a few years ago. It lasted 6 to 8 weeks and now recurrs for a few week at a time if I am ill or under par. Never had it before GA and drs do not know what to do about it other than suggest medication. Sorry, hope that helps.


Do you know if your adrenals are working properly, or if you have adrenal fatigue, as this can affect the way the GA and pre med work.


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