Thyroid UK
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Hi I'm in need of some specialist advice, if im taking prozac will it interfere with the results of thyroid function blood test?

I have been on various anti depressants for the last 11 years, I'm currently on prozac, I tried to come off them before and I managed 6 months it was horrible, after about 2-3 months off the meds I started to experience physical and mental symptoms, shaking hands, pins and needles in hands, dry skin patches, depression, extreme fatigue, obsessive exercise routine, social phobia, hated body image, my periods completely stopped!, the list goes on. At the time I thought it was my body not being able to function without the drugs but doing a bit of research it sounds as tho it could be low thyroid. The doctor has given me a blood form for a thyroid function test and hormone test, he said that the test results won't be effected by the prozac I'm on (30mg), having read into it the active metabolites in prozac metabolise the thyroid hormones that are produced so this would surely interfere with the hormone amounts shown on test results??? Any help much appreciated as struggling with the prospect of going off prozac for at least 5 weeks for it to leave system before I get tested,

7 Replies

I am not medically experienced or trained. However around six months ago I suggested a friend had a thyroid function test - TFT - also B12 - Ferritin - Folate - Iron - VitD. The last 5 came back LOW in their ranges and the TFT's were confusing to say the least ( I live in Crete so we are given our test results automatically ) I explained that I was not able to interpret the TFT results at which point she told me she had been on SSRI's for over 25 years. She started on her supplements - including the Folic Acid to compliment the B12 - and takes T3 - small amounts through the day. This has resulted in her being able to reduce her SSRI's without ill effects for the very first time. She is so happy. Various symptoms she has suffered have also gone away.

Please do not think I am suggesting it is the same for everyone - we are all so different. It is just a positive story.

If you are able to raise your B12 Folates VitD etc. before coming off the Prozac maybe it will be a different experience for you.

Am not sure Docs will support you in this - it is often a lone journey we take to wellness....there are lots of very helpful people on this forum that will be able to support keep posting and reading....


Maybe you've been hypothyroid for a while without your doctor suspecting it. If so, I hope he does a full thyroid function test which includes TSH, T4, T3 and Free T4 and Free T3. Also ask for Vitamin B12, Vit D, iron, ferritin and folate as we can be deficient.

Levothyroxine (a synthetic hormone) which they give us for replacing a dysfunctioning thyroid gland hormone should convert to enough T3 to make us feel well well again. Our receptor cells have to have sufficient T3 in them for us to recover and there are billions in our bodies and our brain contains the most but many do well on levo if they are given an optimum dose and the doctor should raise it gradually over several months till you feel better.

As you are not taking any thyroid gland hormones yet, have your blood test as early as possible in the morning and take your prozac afterwards. Always get a copy of your blood tests, with the ranges, and post if you have a query. If you were taking thyroid gland hormones, it is recommended supplements, vitamins, minerals be taken at least 4 hours later.


Hi thankyou both very much for your helpful posts really appriciate the advice!, I will definately get those checked out thankyou.


If you believe the doctors and the medical profession and big pharma you would nopt be seeking our advice

I can tell you that my husband took Anti depressants for just 6 months and it was hell getting on them and even more hell getting off

He had tried Thyroxine


ONLY Armour thyroid cured everything

1 like

Hi, that's the trouble I don't trust the docs 100% that's why I am on here asking for some advice/experience, iv suffered for the last 11 years il soon be 31 it's gone on too long and I would like to explore all possibilities, iv tried about 7 different anti depressants so trust me I know of the hell your talking about hence not looking forward to coming off the meds if need be to get tested. I don't know what amour is sorry I will have to look that up, thankyou for sharing your experience.


You don't need to come off the anti-depressants to get tested. There is some interaction between thyroid hormones and Prozac but it's likely that taking Prozac is depressing your thyroid function somewhat actually, so it's a good thing the doctor wants to do the tests. The Prozac won't make a thyroid problem look better than it really is, if that makes sense? You may even discover that your mental health issues have been caused by having an underactive thyroid all along - I wonder if maybe you've got a clued-up doctor who realises this? That would be refreshing!


Thankyou, I hope something comes up soon, il post on here after iv been tested and have results!


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