Fluoroquinolone Warnings 2019 update


Fluoroquinolones are very valuable broad spectrum antimicrobial agents. One of their advantages is that they can be given by mouth. In some cases they may be the only oral agent available to treat infection with some groups of bacteria. Antimicrobial resistance to fluoroquinolones has increased in recent years and is now much more common than was the case 10 years ago. Notwithstanding the increasing resistance and the warning outlined below, fluoroquinolones remain an important treatment option for carefully selected patients.


Fluoroquinolones (FQ) including ciprofloxacin, levofloxacin, moxifloxacin and ofloxacin are associated with serious adverse effects on muscles, tendons, bones, the nervous system and the cardiovascular system. Use of fluoroquinolones in older patients, those with renal impairment, solid organ transplantation or on systemic corticosteroids increases the risk of tendon damage.

Fluoroquinolones (ciprofloxacin & levofloxacin) that prolong QT interval should be used with caution in patients receiving medicines known to prolong QT interval (e.g. Class IA and III anti-arrhythmics e.g. amiodarone, tricyclic antidepressants, macrolides, antipsychotics) and in patients with known risk factors for prolongation of the QT interval. See the drugs Interaction Table page for more information.

Moxifloxacin is contraindicated with drugs that prolong the QT interval (see above plus alfuzosin, domperidone, galantamine, indapamide, lithium, macrolides, methadone, quinine sulphate, tamoxifen, tizanidine). This is not a complete list, for a composite list of drugs that can prolong QT interval please consult the relevant SmPC on HPRA website, the BNF or www.crediblemeds.org for further information. NB: Consider OTC medication patient may be taking e.g. domperidone.

A review of Primary Care Reimbursement Service (PCRS) data 2018/2019 shows oral moxifloxacin continues to be used in substantial quantities in primary care in Ireland. This is a cause for concern because circumstances in which moxifloxacin is preferable to other fluoroquinolones with a lower potential for QT prolongation are likely to be exceptionally rare in Primary Care.

Moxifloxacin featured twice in Irish Medicines Board (IMB), now known as the HPRA, Drug Safety Newsletters. In February 2011, the IMB advised: “Due to an increased risk of QT prolongation (in addition to the potential for other serious risks, i.e. serious hepatotoxicity), oral moxifloxacin should only be used when use of other antibacterial agents is inappropriate, or have failed.” The Newsletter also noted that ciprofloxacin, levofloxacin and ofloxacin have lower potential to induce QT prolongation. The increased risk of hepatic adverse effects with moxifloxacin was first highlighted in September 2008 with advice to restrict its use.

The HSE Clinical Lead for Antimicrobial Resistance and Infection Control wishes to emphasise the need for all prescribers and all those dispensing prescriptions to be aware that even in those particular cases where a fluoroquinolone is necessary, moxifloxacin should only be used where other antibacterial agents, including the other fluoroquinolones, are 'inappropriate or have failed'

In 2018, additional warnings on the long term side effects and extended adverse effects of fluoroquinolones including an increased risk of aortic aneurysm and dissection were circulated by the Health Products Regulatory Authority (HPRA) and European Medicines Agency (EMA) following review by the Pharmacovigilance Risk Assessment Committee (PRAC).

The recommendation is that Fluoroquinolones should not be used in the following situations:

  • Patients who previously had serious side effects with a fluoroquinolone
  • For treatment of uncomplicated self-limiting infections (for example throat infections)
  • For prevention of recurring urinary tract infection
  • For prevention of infection e.g. traveller’s diarrhoea
  • For uncomplicated lower urinary tract infection (unless guided by susceptibility testing that indicates that no safe alternative is likely to be effective).
  • For mild or moderately severe infections (unless guided by susceptibility testing that indicates that no safe alternative is likely to be effective)

For patients with certain serious infections (e.g. complicated urinary tract infections) with bacteria that are susceptible to fluoroquinolones, where there is no other suitable oral option, fluoroquinolones remain an important treatment option.

The HPRA recommends that healthcare professionals should advise patients to urgently seek medical advice at the first signs of these adverse reactions involving muscles, tendons or bones or the nervous system (such as feeling pins and needles, tiredness, depression, confusion, suicidal thoughts, sleep disorders, vision and hearing problems, and altered taste and smell). Healthcare professionals should discontinue fluoroquinolone treatment and consider alternative treatment at the first sign of tendonitis, neuropathy or other serious adverse reaction.

Drug Safety Newsletters

Reviewed September 2019