Thyroid UK
87,402 members102,110 posts

fluoroquinolone antibiotics : consider the risks (especially thyroid sufferers)

Fluoroquinolones are certain type of antibiotics that should be used as last resort, but for some reason they are widely used regardless the numerous harmful side-effects they have. For example tendinopathy symptoms might appear just 2 hours after fluoroquinolone exposure! (My dad's achilles tendon ruptured after a course of fluoroquinolones for a minor infection, he was lucky one having just one side-effect which could be fixed by surgery!)

Here I have gathered few links that contain lots of information of fluoroquinolones covering all types of side-effects. Not everyone gets floxed (poisoned) , not everyone get side-effects , but its better to be safe than sorry! For thyroid sufferers it might be best to avoid fluoroquinolones IF possible as the fluorine affects T4 medication.

Dont expect your doctor to tell you about the side-effects of fluoroquinolones, if you develop some you are considered hypocondriac.

"FDA Drug Safety Communication: FDA advises restricting fluoroquinolone antibiotic use for certain uncomplicated infections; warns about disabling side effects that can occur together"

"No other antibiotic carries as high a potential to cause serious, permanent injuries and even death, as the fluoroquinolones do. Despite their higher than normal risks, doctors frequently prescribe them as a first line of treatment even for mild infections. Always ask your doctor if there is a safer alternative.

And, adding insult to injury, most victims claim they were never warned that there are dire adverse effects associated with these antibiotics. I strongly advise you to educate yourself about the risks of fluoroquinolones, and refuse any prescription for these drugs unless absolutely necessary."

"This website was created to describe how Fluoroquinolone Toxicity (FQT) permanently damaged my Thyroid Hormone and Iodine metabolism (TH/Iodine metabolism). “Floxed” is the term used when a person experiences adverse reactions to the fluoroquinolone (FQ) antibiotics. In my case, getting floxed caused major problems with my thyroid system."

10 Replies

That's frightening, and good to know so as to avoid it in future. Thanks for the links. :) I've now added 'floxed' to my vocabulary! :D

1 like



Thank you for posting. We always need to be one-step ahead these days, it would appear.

1 like

I have taken these antibiotics, I had no choice because it was the only antibiotic that would work for my infection, I had no side effects whatsoever, either during or after taking them.

When there is no alternative the benefit out ways any risk.


Yup, but that only proves it has been used correctly in your case!


Side effects can happen, doesn't depend on it being used correctly or not but as in the case of Levo its only the bad stories that are talked about, there will be thousands of people who have been perfectly fine taking these antibiotics.


No I meant in your case it was used correctly as no other option was available.

If it were used as a last resort then the group of people suffering side effects would be smaller. Doesn't take away the fact side effects happen but when it can be permanent damage I wouldn't take fluoroquinolones until I really had to. Simple as that.


We need to be so aware these days. Thanks for posting Justiina.


I have been 'floxed' unfortunately. I have a colonised lung infection and, like bantam12 says there are some infections that are only sensitive to certain antibiotics and Ciprofloxacin (a fluoroquinolone) is apparently the only one that deals with my infection.

I have had a few courses of the lower dose but my lung consultant gave me the higher dose (which my GP doesn't give). I asked the consultant was it OK as I'd read about problems with Cipro, he dismissed me saying it was 'fine'. It made my calf muscles ache a bit and made me very tired but I finished the course. A week later the infection was back and my GP repeated the course of the higher dose. This time I was having stabbing pains around the midriff area and around the back, front and side of my ribs and I ended up feeling as though I'd been kicked in the ribs. When I went back to the GP he told me to stop the Cipro, examined me and said it looked as though my rib cartilage has been damaged. It's taken two weeks off it for the rib pain to subside to a dull ache but I'm still getting some twinges around the midriff - not sure what that is so I will be discussing with my GP.

You can get side effects of these drugs months after stopping them. My GP did say it was a nasty antibiotic, saying it was 'poison', but it was the consultant's decision to give me the stronger dose.

So although I had been OK for the first few courses (over a couple of years), it looks as though I've now been affected by it and probably wont be able to take it again. I now understand that there are IV antibiotics that can be used when I next have a flare up of this colonised lung infection.

As for

"And, adding insult to injury, most victims claim they were never warned that there are dire adverse effects associated with these antibiotics. I strongly advise you to educate yourself about the risks of fluoroquinolones, and refuse any prescription for these drugs unless absolutely necessary."

There is always a patient information leaflet included in the box and side effects, including the serious ones, are included. A patient cannot say they weren't warned, the warning is there if the patient can be bothered to read the leaflet and then address any concerns and possible alternative treatment with their doctor. I tried to discuss them with the consultant, I suppose because the side effects can be quite rare he may never have had a patient affected by them so he dismissed my concerns, but I did know of the problems and went ahead and took them because I didn't know there could be an alternative at the time.


Yeah unfortunately for some infection fluoroquinolones are the only option and then one has to accept the possibility of these harmful side effects. It's no can do until better antibiotics are discovered. Or possibly some sort of solution to prevent this damage!

I strongly agree we should read the leaflet but we have been taught to trust the doctors. Who would imagine antibiotics could cause you severe depression? Not the first thing you could imagine and we end up assuming diarrhoea is the worst side effect as that what antibiotics used to cause.

When we do read about the meds then some doctors judge us idiots and that we have imagined the side effects. It's tricky situation.


You may also like...