Thyroid UK
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Cipro and thyroid???

I have just thrown out my last dose of Cipro. Since taking it I have had symptoms of low thyroid and my levels were just tested before and were fine. I was wondering if anyone else has taking this medication and experienced thyroid symptoms that were exaggerated and if so did you improve after stopping the Cipro? ANY feedback is appreciated. Have read some horror stories about this drug. 

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The paper below clearly refers to taking the cipro with levothyroxine - but without knowing the mechanism, we have no idea if taking them separately by hours could have a similar effect - or not.

Thyroid. 2013 Nov;23(11):1374-8. doi: 10.1089/thy.2013.0014. Epub 2013 Oct 16.

Ciprofloxacin and rifampin have opposite effects on levothyroxine absorption.

Goldberg AS1, Tirona RG, Asher LJ, Kim RB, Van Uum SH.

Author information



Levothyroxine (L-T4) absorption varies between individuals, and can be affected by various concomitantly administered drugs. Case reports have indicated an association between cotreatment with ciprofloxacin or rifampin and hypothyroidism in patients on a stable L-T4 dose.


The effects of two antibiotics on T4 absorption were prospectively assessed in a double-blind, randomized, crossover fashion. Eight healthy volunteers received 1000 μg L-T4 combined with placebo, ciprofloxacin 750 mg, or rifampin 600 mg as single doses. We measured total plasma thyroxine (T4) concentrations over a 6-hour period after dosing using liquid chromatography-tandem mass spectrometry. For each study arm, areas under the T4 plasma concentration-time curve (T4 AUCs) were compared.


Coadministration of ciprofloxacin significantly decreased the T4 AUC by 39% (p = 0.035), while, surprisingly, rifampin significantly increased T4 AUC by 25% (p = 0.003).


Intestinal absorption of L-T4 is differentially affected by acute coadministration of ciprofloxacin or rifampin. Mechanistic studies focused on intestinal and possibly hepatic thyroid hormone transporters are required to explain the observed drug interactions with L-T4.

PMID:    23647409    [PubMed - indexed for MEDLINE]

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Thank you so much for this.

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I have just finished a course of Cipro and haven't noticed any problems thyroid wise, I was expecting to feel awful while taking it but actually felt and still feel better than I have in a long while.

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I've read several blogs which tell the horror stories too - some of the fallout seems to last for years.  I only had one course of it - after being hypo for 4 e years - and never been right since but not sure if I can pin point bit to Cipro. I would not take it again though 

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I hadn't heard of this drug but this is an excerpt from the USA:


Fluoroquinolones, including CIPRO®, are associated with an increased risk of tendinitis and tendon rupture in all ages. This risk is further increased in older patients usually over 60 years of age, in patients taking corticosteroid drugs, and in patients with kidney, heart or lung transplants (see WARNINGS).

Fluoroquinolones, including CIPRO, may exacerbate muscle weakness in persons with myasthenia gravis. Avoid CIPRO in patients with known history of myasthenia gravis (see WARNINGS).

To reduce the development of drug-resistant bacteria and maintain the effectiveness of CIPRO Tablets and CIPRO Oral Suspension and other antibacterial drugs, CIPRO Tablets and CIPRO Oral Suspension should be used only to treat or prevent infections that are proven or strongly suspected to be caused by bacteria.


I read all the bad reviews before starting Cipro but I had no choice in taking it, it was the only one for the infection I had. There are many many good reviews on Cipro, people like me who had no problems at all, I usually have issues with antibiotics but Cipro caused no side effects whatsoever, as I said I felt fine on it.

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I have taken two or three courses of Cipro for Pseudomonas infection in my lungs (I have COPD and, apparently, Pseudomonas colonised). I didn't notice any problems but I think I kept doses of Cipro well away from my thyroid meds.

However, I have since read of some horror stories of some people's reaction to Cipro so it's obvious that it's one of those drugs that some people will react to and others wont.

I'm just getting over pleurisy and pneumonia. Before diagnosis I was wondering if it was Pseudomonas flaring up again and I really didn't want to take Cipro. I discussed this with my GP, telling him that one of the doctors (now retired) had given me an emergency supply to start if I felt the need and the surgery was closed for the weekend, bank holiday, etc. Current GP said they would now not prescribe Cipro, they prefer to use something else. I told him I was happy to hear that as I didn't want to take it again and would prefer to dispose of the pack I had. I was surprised though, I thought Cipro was the only antibiotic that Pseudomonas was sensitive to.


Glad to hear they wont prescribe it. I wont touch it again either. I didn't space it out but an hour between my thyroid meds so I sure that wasn't a smart decision. Just couldn't understand why the wouldn't write something different given that they knew I was on thyroid meds. 


I had Pseudomonas and Cipro was the only antibiotic that would work. I will happily take it again if it sorts the problem.

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Just for information, as it's up to individual choice, and I'm the sort that reads patient information leaflets and and looks for information, here are some sites regarding Ciprofloxacin that are worth reading. It's obvious that some people are going to suffer problems after taking Cipro, and others will not (me included with the two or three courses I've taken so far)

There seems to be plenty more evidence out there.

If I get another flare up of Pseudomonas I will be having more discussions with the GP who told me they now prefer to prescribe something else. I personally don't want to risk taking it again.


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