A Canadian study paints a grim picture of liver injuries caused by fluoroquinolones.

Fluoroquinolones are a class of antibiotics. These drugs include Cipro, Levaquin, Avelox, and other common antibiotics. This family of antibiotics was developed starting in the 1960s.

Unlike older antibiotics, quinolones like fluoroquinolones are purely synthetic; earlier antibiotics were either produced by bacteria and fungi or based on chemicals from bacteria and fungi. It was hoped that since quinolones, including fluoroquinolones, were artificial, bacteria would have a harder time resisting them. While this has not proven to be the case, quinolones have proven quite effective and joined the ranks of widely used antibiotics. However, safety concerns have arisen, particularly around liver failure and liver damage.

In a 2012 study published in the Canadian Medical Association Journal (CMAJ), a peer-reviewed medical publication, researchers found that fluoroquinolones carried the risk of liver failure. The researchers used a population-based, nested case-control study using data collected through Canada’s healthcare network from 2002 through 2011. In this type of study, researchers compare the characteristics of someone who suffers a disease or medical conditions, and compares them to people who don’t have the condition. This type of study is relatively low-cost and easy to perform compared to other types of studies, but cannot assert a connection as strongly as some other types of studies, including clinical trials.

The CMAJ study found that while liver toxicity was a rare side effect of fluoroquinolones, when it did happen, it could be severe. The healthcare data contained 144 patients who suffered liver toxicity after taking one of the drugs. Nearly two-thirds (61.1 percent) died from liver failure. The researchers did note that moxifloxacin, the technical name for Avelox, was associated with the highest risk of acute liver failure among the fluoroquinolones. The researchers noted that these drugs were associated with a risk of liver toxicity, even in patients without existing liver problems.

A class action lawsuit investigation has been launched to explore the possibility of a fluoroquinolones lawsuit against drug makers. Such a lawsuit may allege that drug makers were aware — or reasonably should have been aware — of the risk of serious fluoroquinolones side effects like liver failure, liver toxicity, and others complications. Such a lawsuit could further allege that not only were drug makers aware, but that they deliberately downplayed the risk, endangering the public.