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Fluoroquinolone Antibiotics

The popular class of antibiotic drugs, known as Fluoroquinolones, can fight infections but may increase the risk of heart problems and other complications. Cipro, Avelox and Levaquin are part of this drug class.

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Fluoroquinolone antibiotics are a class of antibiotics used to treat a variety of bacterial infections. The approved uses for each of the fluoroquinolones drugs are slightly different, but similar.

FDA-approved uses include combating bacteria that cause urinary tract infections, certain sexually transmitted infections, bacterial bronchitis, pneumonia, sinusitis, typhoid fever, septicemia, joint and bone infections, soft tissue and skin infections, and bacterial gastroenteritis. 1 People generally refer to bacterial gastroenteritis as food poisoning.

These antibiotics have been associated with an increased risk of complications, including aortic dissection and aortic aneurysm.

Types of Fluoroquinolones

In the United States, the following types of fluoroquinolone antibiotics are currently prescribed: ciprofloxacin (Cipro, Cipro XR, Proquin XR), gemifloxacin (Factive), levofloxacin (Levaquin), moxifloxacin (Avelox), norfloxacin (Noroxin), and ofloxacin (Floxin). 1

Other types of fluoroquinolone antibiotics include lomefloxacin (Maxaquin) and sparfloxacin (Zagam). The brand name versions of these drugs are no longer available in the United States. Generic versions may still be available. 2 Respiratory fluoroquinolones may be used to fight pneumonia.

The first quinolone antibiotic, nalidixic acid, was discovered in 1962. 3 The most popular quinolone is Cipro and the second most common is Levaquin.

The fluoroquinolone antibiotics in use today are modified versions of nalidixic acid. The first brand approved by the U.S. Food and Drug Administration (FDA) was Norfloxacin, introduced in 1986. Others followed in the 1980s and 1990s. 4 The mechanism of action for quinolone antibiotics involves blocking DNA replication.

Tendon Rupture FDA Warning

Although FDA-approved to treat certain types of bacterial infections, fluoroquinolone antibiotics are not without risks. In recent years, the FDA has issued several safety alerts and warnings about fluoroquinolone antibiotics. 5

In 2008, the FDA notified manufacturers of fluoroquinolone antibiotics of the need to “add a boxed warning to the prescribing information about the increased risk of developing tendinitis and tendon rupture in patients taking fluoroquinolones.” At that time, the FDA recommended for healthcare professionals to consider that “fluoroquinolones are associated with an increased risk of tendinitis and tendon rupture.” 6

The FDA issued a safety alert regarding these antibiotics in 2016. The update provides restrictions when using fluoroquinolone drugs to treat uncomplicated infections and indicates that disabling side effect may occur.

The aorta is also made up of these kinds of collagen, leading the authors to suggest that fluoroquinolone antibiotics may be associated not only with the rupture of tendons, especially the Achilles, but also aortic dissection and aneurysm.

Quinolone Antibiotic Complications

In late 2015, two studies published in reputable medical journals linked fluoroquinolone antibiotic use with the possibility of aortic dissection or aortic aneurysm. These conditions are life-threatening and can lead to death. 7

The two studies, published in BMJ Open and JAMA Internal Medicine, note past research that suggests the mechanism for the risk of tendon injury occurring with use of fluoroquinolones may include “degradation,” or deterioration, of type I and type III collagen. The aorta is also made up of these kinds of collagen, leading the authors to suggest that fluoroquinolone antibiotics may be associated not only with the rupture of tendons, especially the Achilles, but also aortic dissection and aneurysm. 7

Despite these potential complications, there hasn’t been an antibiotic recall of fluoroquinolone drugs.

Fluoroquinolones and Aortic Dissection

One of the studies, published in JAMA Internal Medicine, indicates that fluoroquinolone antibiotics may be linked to aortic dissection and aortic aneurysm. The study, comprised of people who experienced aortic aneurysm or dissection and matched controls, found current fluoroquinolone use (defined as having a prescription filled in the 60 days prior to the adverse event) to be associated with a significantly more than doubled rate of aortic aneurysm or dissection. The significantly increased rate held when fluoroquinolones had been used within the year prior to the aortic dissection or aortic aneurysm. 8

An aortic dissection involves the tearing of the inner layer of the aorta. The aorta is the main artery in the body, which carries oxygenated blood from the heart so that blood may be distributed throughout the body. 9

If the aorta tears, blood can flow through the tear, causing, as described by the Mayo Clinic, “the inner and middle layers of the aorta to separate (dissect). If the blood-filled channel ruptures through the outside aortic wall, aortic dissection is often fatal.” 10

Fluoroquinolones and Aortic Aneurysm

The studies also indicate that fluoroquinolone antibiotics may be linked to an aortic aneurysm. The study published in BMJ Open found a significantly more than twofold increased hazard of aortic aneurysm with current use of fluoroquinolone antibiotics. 11

An aortic aneurysm is “an abnormal enlargement or bulging of the wall of the aorta.” 11 If the aneurysm grows large enough, “it can burst and cause dangerous bleeding or even death.” 12

Side Effects of Fluoroquinolones

Typical side effects of fluoroquinolone antibiotics include skin rash and allergic reactions, gastrointestinal problems, and headaches. Less common but more serious side effects include seizures, hallucinations, tendon rupture, QT prolongation (a problem with the heart’s rhythm), nerve damage, angioedema and photosensitivity. 13

  1. http://livertox.nih.gov/Fluoroquinolones.htm
  2. http://www.rxlist.com/zagam-drug.htm; http://www.rxlist.com/maxaquin-drug.htm
  3. http://cid.oxfordjournals.org/content/41/Supplement_2/S113.long; http://www.cdc.gov/HAI/settings/lab/Quinolones-Clinical-Laboratory.html
  4. http://www.cdc.gov/HAI/settings/lab/Quinolones-Clinical-Laboratory.html
  5. http://www.fda.gov/Drugs/DrugSafety/ucm365050.htm; http://www.fda.gov/Drugs/DrugSafety/InformationbyDrugClass/ucm346750.htm; http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm126085.htm
  6. http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm126085.htm
  7. http://archinte.jamanetwork.com/article.aspx?articleid=2451282
  8. https://my.clevelandclinic.org/services/heart/heart-blood-vessels/aorta
  9. http://www.mayoclinic.org/diseases-conditions/aortic-dissection/basics/definition/con-20032930
  10. http://bmjopen.bmj.com/content/5/11/e010077.full
  11. https://my.clevelandclinic.org/services/heart/disorders/aortic-aneurysm
  12. https://www.nlm.nih.gov/medlineplus/aorticaneurysm.html
  13. http://livertox.nih.gov/Fluoroquinolones.htm; http://www.fda.gov/Drugs/DrugSafety/DrugSafetyPodcasts/ucm365346.htm