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Dear Doctor Letter

Yellow Card reports

Academic Book

MHRA Review

EMA review
DSUs and Warnings


Information for your GP

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We have produced the letter below to show your doctor that your symptoms are real and not just in your head. It's deliberately short and gives just a few references so he/she should manage to read it during an appointment. The letter text is below, in bold, dark blue.  Just copy and paste it into a document, add a date – and add your name if you want to, then print.


Understanding Serious  Reactions to Fluoroquinolones


Dear Doctor,

Serious Adverse Reactions to Fluoroquinolones are NOT “very rare” and potentially anyone might experience them.

The fluoroquinolone (FQ) antibiotics come with a huge list of warnings about possible side effects, many of which are described as rare or very rare. The SmPCs state that the benefits outweigh the risks, although you may be aware that some indications were removed in March 2019 (e.g. simple UTI). This letter was written by us, Quinolone Toxicity Support UK, to briefly explain why the FQs are not ‘just’ an antibiotic, why any patient is liable to suffer from ADRs. and, in many cases, why the risk of life changing harm far outweighs the benefit.


In 2018 the European Medicines Agency (EMA) reviewed ADRs to FQs, and in March 2019 published a report which documented their non-clinical aspects (i.e. the mechanisms of action). The conclusion was that oxidative stress and mitochondrial toxicity are behind most of the symptoms. [1].

Any patient is liable to suffer harm simply because every patient has

mitochondria. The SmPCs clearly tell you that “the bactericidal action of (the FQ) results from the inhibition of both type II topoisomerase (DNA-gyrase) and topoisomerase IV, required for bacterial DNA replication, transcription, repair and recombination.”  What they don’t make clear is that mammalian mitochondria also need both type II topoisomerase and topoisomerase IV for their DNA replication, transcription, repair and recombination, and thus are inhibited along with the bacteria.

The EMA and MHRA both say it is not “helpful” to discuss with HCPs how the bactericidal action of fluoroquinolones is achieved.  However, given there is no known treatment for the side effects, we at QTSUK believe you might prefer to know that by prescribing this unique class of antibiotic you risk causing “disabling and potentially long-lasting or irreversible side effects” (i.e. a secondary mitochondrial disease).


Delayed adverse reactions

The MHRA make clear that, if a patient taking an FQ reports side effects, the drug should be stopped immediately. What they don’t say is that there is no known treatment, nor can they advise what to do next. It’s also worth remembering that ADRs might not start (or be noticed) until several weeks or even months after cessation of the drug – and these can be equally as serious and long lasting as any that start immediately [2].

How many cases?

The frequency of the severe adverse reactions is stated as being very rare although the MHRA estimate that only 10% of any side effects are reported. The Yellow Card figures show an average of 27 new reports of serious adverse reactions are received every month (since March 2019), which perhaps indicates that 270 people per month have been seriously (potentially irreversibly) harmed over the last four years – or around 13,000 since the new warnings were issued. [3].

The MHRA Yellow Card figures do not include those patients whose HCPs had no idea that their very real pain resulted from an FQ antibiotic. There must be many people who simply do not realise that the painful symptoms they’ve suffered from for many years (often diagnosed as fibromyalgia and or CFS/ME) are due to an antibiotic.


The MHRA reviewed FQ side effects for themselves in May 2023 and we, as patient experts, were invited to work with them and also to make a presentation to the the Commission for Human Medicines on the 25th of May. As a result they will be issuing a new DSU and have also promised to look at further methods to both raise awareness and reduce FQ use to a minimum.

You have probably seen that several DSUs with regard to fluoroquinolones have already been issued e.g. in 2008, 2012, 2014, 2018 (risk of aortic dissection), March 2019 (see above), May 2019 (hypoglycaemia and mental health problems), and Dec 2020 (risk of heart valve regurgitation).

We are aware, however, that many specialists who prescribe an FQ will never actually know if a patient suffers ADRs, because the patient will naturally go to their GP if they have leg pain or gut problems. Therefore, we ask that you look back at what your patient has been prescribed, as any side effect can be serious, long term or even permanent (e.g. peripheral neuropathy). We know there is no known cure as yet and do appreciate that your time is limited due to other pressures, but your belief and understanding will help your patient enormously.

Tolerance thresholds

It is really important for all HCPs to be aware that a few patients might react immediately after just one tablet, whilst many others can successfully take one or more courses before they reach their tolerance threshold. Please don't assume a patient will not react to an FQ because they did not react to a previous course. Also, please be aware that someone who has shown only a mild reaction in the past will most likely have very severe reactions if there is a next time. Studies show that the effects are cumulative over one or more courses [4] and that reactions rarely present as a single symptom. They can appear in any combination, or as a cluster of seemingly random and unconnected symptoms, up to perhaps 12 months, possibly more, after cessation of the drug [2].

More information

There are many academic papers regarding both the short-term and long-term dangers of FQs and we have given the URLs of some examples below. One published in 2018 [5] discusses how FQs damage mitochondrial DNA (although this was known in 1996) while one from 2017 [6] describes the biochemical disruptions to every cell process.  We hope you find these useful.


Quinolone Toxicity Support UK was founded in 2015 to help and provide information to both sufferers and medical professionals in the UK. We appreciate you reading this letter and ask that you share the information with your medical colleagues.


Thank you,


Miriam Knight


Quinolone Toxicity Support UK


August 2023





See section 2.2 Mechanisms of action on pages 4-7.
Quote taken from conclusions p.7

For full overview of the Review and transcript and video of Public Hearing go to:


Fluoroquinolone-induced serious, persistent, multisymptom adverse effects.

Beatrice Golomb 2015, (Paywall - also at...

Golomb et al.





Mechanisms of Pathogenesis in Drug Hepatotoxicity Putting the Stress on Mitochondria. Dean P. Jones et al. April 2010 (Threshold Effects in Mitochondrial Toxicity).



Ciprofloxacin impairs mitochondrial DNA replication initiation through inhibition of Topoisomerase 2. Hangas et al Oct 2018



Treatment of the Fluoroquinolone Associated Disability - The Pathobiochemical Implications. Michalak et al. 2017



Yellow Cards


It's very important that you report your Adverse Reactions to MHRA (Medicines and Healthcare Products Regulatory Agency) via the Yellow Card Scheme.  We suggest you also update your report every 6 months or so to report your changing symptoms, so MHRA  get a better understanding of how long things can last or when new ADRs can occur (use the reference number they give you when updating). Your doctor or pharmacist should also be advised and they may possibly send in a Yellow Card as well.

Go to this link and follow the easy instructions.  It helps if you have the packaging with you as they ask for the batch number and dates the drugs were taken (but don’t worry if you haven’t got this information – the important thing is to report your side effects). If you feel you can't do this yourself, ask someone to do it for you.  MHRA actively encourage patients to register any potential side effects from any drug and to update frequently if the effects continue. They also want doctors to send in reports even if they only suspect that a drug may be causing a problem, although most doctors don't seem to be aware of this.

You can also email MHRA directly for information about  fluoroquinolones such as updates to the Patient Information Leaflets (PILs), statistics of how many people have been affected etc.  We believe it's important to keep reminding them about how dangerous these drugs are, so the more emails they receive the more notice they'll have to take.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~                                        ~~~~~~~~~~~~~~~

Academic Book about fluoroquinolone toxicity

The only academic book we are aware of that details FQ Toxicity, diagnostic tools and possible treatments is:
Fluoroquinolone Associated Disability (FQAD) By Stefan Pieper
published by Springer in 2021.

The author, Dr. Stefan Pieper, has a clinic in Konstanz, Germany, specialising in not only general medicine but also homeopathy, acupuncture and rescue medicine. He became interested in FQ damage when he started to notice the harmful effects of drugs like Cipro on patients that came to him for help from all over Germany and beyond (more than 700 at the time of writing the book and many more now). In an interview he said he decided to write it:

“In order to give as many primary care physicians and sufferers as possible the opportunity to inform themselves quickly and comprehensively about the subject”.

In his book Dr Pieper highlights many of the issues surrounding this class of drugs under the following headings:

  1. Introduction to FQAD

  2. FQAD and oxidative stress | mitochondrial toxicity

  3. FQAD and musculoskeletal damage | collagen disorders

  4. FQAD and neurotoxicity | peripheral neuropathy |

  5. FQAD and neuropsychiatric adverse effects

  6. Diagnostic criteria

  7. Practical experience


It’s available for around £22 on sites such as Amazon e.g.

(You can read a few sample pages on-line)

Many of our members find this book useful to show their GP or other professional as it demonstrates at least one professional out there acknowledges FQAD (or FQT) actually exists!

Disclaimer: However, we are a support group, not a medical organisation. We can not endorse any medical doctor or treatment protocol and do not receive any “commission” for book or other purchases or medical treatment.

2023 MHRA Review

In February 2023 six members of our group attended a teleconference with 4 key members of the MHRA review team. We were asked, as patient experts, for input on the scope of their upcoming review of ADRs to FQs. We were sent written notes summarising the meeting which outlined our suggestions and what the MHRA proposed to do in order to raise awareness and minimise risks.

Briefly, we mentioned:

1.Lack of HCP awareness - which MHRA stated was “a key component of the effectiveness of measures to minimise these risks” and would be “carefully considered as a central part of the MHRA review”.

2.Concerns about the effectiveness of current measures to minimise risks – to which the MHRA said they “will consider the appropriate regulatory action to take.... This will include considering the points raised about information given to patients, the content of the current regulatory product information, the use of fluoroquinolones in urological infections, and the use of fluroquinolones for suspected infections.”

3.Mechanisms (e.g. effects on mitochondria, GABA receptors, and vagal tone as mechanisms for disabling and/or long-lasting ADRs) - which the MHRA stated will be “included as part of the scope of the review”.

4.Factors that increase risk: (e.g. use of steroids/NSAIDs, genetic deficiencies such as G6PD, hypermobility, age) – to which the MHRA replied that they will “consider the available information about ...potential risks associated with medical conditions, specific patient groups, or the use of other medicines (apart from NSAIDs).” adding “where this is not possible, the MHRA commits to further work to address them separately.”

5.Psychological impacts: - which the MHRA stated they will address by adding

“...a section to the review, which will cover the psychological ADRs and psychological impacts...This will contribute to the overall assessment of what actions are warranted in terms of risk minimisation measures.

6.The importance of having a recognised diagnosis: to which the MHRA stated they “will note the lack of a widely used definition and the lack of medical codes”.

7.Under-reporting of ADRs; issues with the Yellow Card Scheme: because of under-reporting we believe many healthcare professionals do not consider the possibility that the symptoms could be caused by a fluoroquinolone. The MHRA replied they will note our concerns and also ensure they are raised with the relevant department.

8.Lack of available treatments: - to which the MHRA said they “will note the lack of treatment options in the review, and consider this as part of the section on the effectiveness of current risk minimisation measures”.

We cited the following papers as part of our evidence :

“Fluoroquinolones-Associated Disability: It Is Not All in Your Head.”

Freeman, Maya Z., et al.

“Fluoroquinolone-induced serious, persistent, multisymptom adverse effects.”

Golomb, Beatrice Alexandra et al. (link above in doctor's letter).

Selective antagonism of the GABAA receptor by ciprofloxacin and biphenylacetic acid

M. A. GreenR. F. Halliwell

First published: 11 February 2009

“Treatment of the Fluoroquinolone-Associated
Disability: The Pathobiochemical Implications.”

Michalak, Krzysztof et al. 2017

Go to our page "Academic article 2017" for link plus our 'easy-reading' version of this very important article (seen and approvedof by the authors).

Fluoroquinolone-Associated Disability (FQAD)

Stefan Pieper 2021 - see above. 

This summary ran to over 4 pages plus a further page of references. In June they sent everyone who contributed to the review (with their story or suggestions) the following email setting out the actions they will now undertake:

From , Scientific Assessor, MHRA Safety & Surveillance Group

In my previous e-mail, sent on 19 April, I said that MHRA was carrying out an assessment of relevant data, and would be seeking advice from independent expert groups.  This process was completed at the end of May.

The MHRA will now take the following actions:

1. We will remind UK healthcare professionals about the risk of long-lasting, disabling and potentially irreversible side effects associated with fluoroquinolones.  As a first action we have required manufacturers of fluoroquinolone medicines to send a safety letter to a wide range of UK healthcare professionals.  We also plan to include an article in the August issue of Drug Safety Update (DSU) to raise awareness among healthcare professionals about the risk of disabling and potentially long-lasting or irreversible adverse drug reactions.  DSU is a monthly publication which MHRA uses to communicate important medicines safety information to UK healthcare professionals;

2. We will carry out further work to look at additional regulatory actions that it may be appropriate for MHRA to take in the UK, taking into account the independent expert advice we received in May.  For example changes to the current regulatory advice for healthcare professionals in the product information about situations where fluoroquinolones may be prescribed and the warnings about the risk of disabling and potentially long-lasting or irreversible adverse drug reactions (ADRs).  Additional regulatory action may be accompanied by more communications to UK healthcare professionals if appropriate.  We will provide a further update about this in due course;


3. The data reviewed by MHRA, including patient accounts of their experiences, highlighted the importance of improving awareness of this risk across the UK healthcare system.  The MHRA will work with other bodies that are part of the UK healthcare system, for example NICE, so that they are aware of the MHRA review and can take any appropriate actions that are within their remits. 

On behalf of the MHRA I would like to thank everyone who has contributed to our review of fluoroquinolones.”

We will update this page with any reminders or letters they send out. Meanwhile, we can’t help but think they took a lot of time to do very little!

EMA Review 2018

The European Medicines Agency (EMA) reviewed the “persistence of side effects known to occur with quinolone and fluoroquinolone antibiotics” in 2018. This included a Public Hearing in June 2018 where patients/carers and health professionals from all over Europe came together to give evidence to the Review Committee (PRAC). As a result, in March 2019 the older (and rarely used Quinolones) were withdrawn and some restrictions were placed on the use of Fluoroquinolones (please see the bottom of this section).

At that time, the UK was still in the EU and the MHRA was part of the EMA, so we were fully involved in this review. Miriam Knight gave evidence on behalf of this group and several of our members also spoke as individuals, telling their own painful stories. We were happily surprised that many of the medical professional speakers also stated how serious – and dangerous – the side effects can be.
The transcript of the statements can be seen by clicking the link below, then on ‘public hearing’, then ‘written interventions’ – click on individual speaker's names. The video is found below the table of languages and we suggest you click to watch it on YouTube. You can then see the list of individual speakers and their times by clicking 'show more' under the video.

The summary of the final and legal decision of the EMA Review, titled:
Disabling and potentially permanent side effects lead to suspension or restrictions of quinolone and fluoroquinolone antibiotics (March 2019)

can be found at this link.

We, however, find the Assessment Report much more interesting  as it details the mechanisms of action of the fluoroquinolones. It’s 86 pages long but we strongly suggest it’s worth reading just the 3 pages of the “non-clinical aspects” (section 2.2 pages 4-7). These mechanisms are what the MHRA and EMA don’t think doctors need to know ('non-clinical'). This is where they list oxidative stress, mitochondrial damage, tendon damage, apoptosis (cell death), chelation (depletion) of metal ions, neurotoxicity, neuropathy, phototoxicity and vasculitis. We believe ALL doctors and all HCPs DO need to know about this!

The full Review Assessment Report can be found at:



The links below are to previous MHRA Drug Safety Updates (DSUs) followed by the US Food and Drug Administration (FDA) alerts. Although Europe seems to lag behind the USA, there’s no evidence in the US support groups to show that their doctors have any better grasp of the dangers than here in Europe.

​N.B. The 2019 European Review (above) stated “The majority of scientific publications focused on ciprofloxacin, levofloxacin and ofloxacin that are the fluoroquinolones predominantly used in clinical practice. From the available information, the PRAC considered that the potential mechanisms of the abovementioned disorders would be relevant for all (fluoro)quinolones (class effect).” We believe the principle of the “class effect” would also apply to the DSUs issued prior to ths statement.


Dec 2020 - risk of heart valve regurgitation:

March 2019 – Class restrictions issued post EMA Review

MHRA also issued this Central Alert (CAS) – something they apparently rarely do.

​November 2018 - increased risk of aortic aneurysm:


​September 2014 – levofloxacin restrictions:

January 2011 – moxifloxacin liver reactions:      


2008 - moxifloxacin – see page 8)  

“...Moxifloxacin now restricted for use only when other medicines cannot be prescribed, or have failed, for treatment of acute bacterial sinusitis, acute exacerbation of chronic bronchitis, or community-acquired pneumonia. This restriction is based on evidence of an increased risk of life-threatening liver reactions and other serious risks associated with moxifloxacin”

Our note – compare this wording to the near identical restriction issued in 2019 – 11 years later!

FDA Alerts:

The FDA issued two new warnings about the risks of fluoroquinolone adverse reactions in 2018, the first was concerning  low blood sugar levels and mental health side effects [07/10/2018]

FDA Fluoroquinolones and Diabetes - Drug Safety Communication.pdf

while the second was about increased risk of ruptures or tears in the aorta blood vessel in certain patients [12-20-2018]

Prior to these announcements the FDA issued major restrictions and recommendations in July 2016

or the full pdf can be read here – but it's 69 pages long.,020635s073,021721s034lbl.pdf)

We’ve taken the main points from the the press announcement:

“It’s important that both health care providers and patients are aware of both the risks and benefits of fluoroquinolones and make an informed decision about their use.”

“...fluoroquinolones are associated with disabling side effects involving tendons, muscles, joints, nerves and the central nervous system. These side effects can occur hours to weeks after exposure to fluoroquinolones and may potentially be permanent.”

“Because the risk of these serious side effects generally outweighs the benefits for patients with acute bacterial sinusitis, acute exacerbation of chronic bronchitis and uncomplicated urinary tract infections, the FDA has determined that fluoroquinolones should be reserved for use in patients with these conditions who have no alternative treatment options. For some serious bacterial infections, including anthrax, plague and bacterial pneumonia among others, the benefits of fluoroquinolones outweigh the risks and it is appropriate for them to remain available as a therapeutic option.”

Incidentally, during the 2016 US Presidential Race between Hillary Clinton and Donald Trump it was revealed that Mrs Clinton had been prescribed a 10 day course of Levaquin (levofloxacin) for mild pneumonia.  (  This is one of the illnesses the FDA had just announced  it shouldn't be used for!

This one from August 2013 required ALL fluoroquinolone packaging (except eye and ear drops) to carry warnings of the “serious side effect of peripheral neuropathy” which may become permanent.

​In February 2011, the risk of worsening symptoms for those with myasthenia gravis was added to the Boxed Warning.

The FDA issued this alert in July 2008 instructing manufacturers of fluoroquinolones to add a boxed warning (known as a Black Box) to highlight the dangers of the increased risk of developing tendinitis and tendon rupture with taking these drugs.




The British Medical Journal is one of the world's oldest yet highest-ranking medical journals so we were delighted when they published two papers about fluoroquinolones in September 2015.

FQ-induced serious, persistent, multisx, adverse effects - BMJ case reports.PDF

This demonstrates that fluoroquinolones cause persistent multisymptom adverse effects.

This concludes that fluoroquinolones are associated with subsequent tendon ruptures and may also contribute to aortic aneurysms.

This third paper was published in 2002 and demonstrates a link between fluoroquinolones and tendinitis, especially in those over 60.  An increased risk was seen if corticosteroids were taken at the same time.


Other Journals

Published in Nature Magazine 2018.

This is a useful paper published in the Journal of Athletic Training in June 2014, which outlines the dangers of applying normal sports injury techniques to fluoroquinolone damaged tendons.    The British Journal of Clinical Pharmocology published this article in 2011, describing the neurotoxic effects of the different groups of antibiotics.  Scroll down 4 pages to see Table 2, and fluoroquinolones are discussed at the bottom of that page.


Daily Mail Articles

The Daily Mail has featured fluoroquinolones quite a few times over the years with the first article that involved QTSUK being published in May 2016, after we contacted them.  - 14 September 2020  -  28 January 2019  -  The Mail on Sunday, 27 October 2018  -  23 July 2018  -  16 May 2016  -  17 February 2016
  -  7 February 2012


Other Articles

Published in The Herald (Scotland), October 2018

Published in November 2015, this paper shows how antibiotics disrupt your gut – for up to 12 months in the case of ciprofloxacin. For the less colourful but full academic paper go to

Another Washington Post story, and very informative.

The journalist himself had a brief episode of being floxed - 2012.

Published in 2011 – nothing's changed.

Published as 'New Cipro, Same Side Effects' in the Washington Post December 2002, this article discusses the introduction of Cipro XL, the one a day tablet.  It also usefully mentions the 2000 postal workers from North East Washington who were put on a 60 day course of Cipro after 2 colleagues died from anthrax exposure the previous year.

One of our members is bravely writing a blog about his life, his symptoms and his ups and downs.  You may like to read it to see what happens, to sympathise, or to just say you never knew.

There are links to over 200 academic papers and media articles on the Floxie Hope website plus many articles written by Lisa Bloomquist herself.

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