Study Links Avelox, Levaquin and Liver Injury Risk for Seniors

The findings of a new study suggest that the side effects of Levaquin and Avelox, two popular antibiotics that are part of a class of medications known as fluoroquinolones, may increase the risk of severe liver injury in older patients. 

The research was published this week in the Canadian Medical Association Journal (PDF) by researchers from the Canadian Drug Safety and Effectiveness Research Network, who found that users of Levaquin (levofloxacin) and Avelox (moxiloxacin), who are over the age of 65, may be twice as likely to experience liver injury, when compared to the use of clarithromycin, a macrolide antibiotic sold under the brand name Biaxin.

The Canadian researchers looked at data on 144 Ontario patients over 65, who were hospitalized between April 2002 and March 2011 due to liver injuries less than a month after receiving antibiotics used to treat respiratory infections. Eighty-eight of the patients died while in the hospital and none had a previous history of liver disease.

Researchers determined that Avelox had the strongest association, at more than double the risk of non fluorquinolone antibiotics. However, Levaquin appeared to generate a “statistically significant” increase in liver injury as well.

The overall risk of liver injury from Levaquin and Avelox still appears to be low, according to the researchers, with about six liver injury hospitalizations for every 100,000 elderly patients exposed to one of the antibiotics.

Canadian officials issued an Avelox liver injury warning as early as March 2010, but this study appears to suggest the risk may apply to other medications that are part of the same class of drug. Fluoroquinolone antibiotics are most commonly used to prevent infections by hindering bacteria reproduction.

All of the drugs of this class have also been linked with an increased risk of tendon ruptures, but that risk appears to be greatest with Ortho-McNeil-Janssen Pharmaceuticals, Inc.’s Levaquin (levofloxacin). According to reports received by the FDA, Levaquin tendon ruptures accounted for 61% of all fluoroquinolone-associated ruptures between November 1997 and December 2005. However, the drug only accounted for about 45% of all prescriptions written for fluoroquinolones during that time.

Johnson & Johnson and their Ortho-McNeil-Janssen Pharmaceuticals subsidiary has faced more than 3,700 lawsuits over tendon ruptures from Levaquin brought by individuals throughout the United States.  All of the complaints involve similar allegations that the drug maker failed to adequately warn about the risks associated with the medication, or provide information to consumers and the medical community that the medications should be stopped if tendon pain develops while taking the antibiotic. As of June, a number of the Levaquin tendon rupture lawsuits had been settled.

Earlier this year, a study published in the Journal of the American Medical Association (JAMA) found that individuals from Canada who took a fluoroquinolone were also five times more likely to suffer retinal detachment, which occurs when the retina peels away from its underlying layer of support tissue.