Among the most widely prescribed antibiotics in the world are Cipro (ciprofloxin), Levaquin (levofloxacin) and Avelox (moxifloxacin). These drugs are members of the quinolones family, which a recent study shows may increase the risk for liver injury, liver toxicity, or Stevens Johnson Syndrome (SJS).

This research comes from J. Michael Paterson, MSC, and colleagues in Toronto, Ontario. Scouring the Ontario Drug Benefit Database and the CIH Information Discharge Abstract Database, they looked at a spectrum of older outpatients (age 66 and above) with no history of liver disease who had received antibiotics. The CIH database provided diagnostic and procedural information for all acute care hospitals admissions in Ontario; it was used to identify hospital visits for acute liver injury from April 2002 to March 2011.

The researchers’ focused on patients who had been admitted to the hospital within 30 days of receiving a prescription for one of the following commonly used antibiotics: clarithromycin, cefuroxime, moxifloxacin, levofloxacin, or ciprofloxacin. Of 746 patients identified, they used 144 as comparison against a control group who received the quinolone antibiotics, but did not end up in the hospital. The mean age of the patients was 77 years.

Their findings, published Aug. 13 in the Canadian Medical Association Journal, showed that for this segment of the population moxifloxacin (brand name Avelox) and levofloxacin (brand name Levaquin) may increase the risk of acute liver injury. In fact, “88 of the patients with liver injury, or 61.1 percent, died during their index hospital admission.”

These quinolone side effects have led to a number of lawsuits seeking compensation from drug makers for failing to warn patients about these increased risks.

Quinolone Antibiotics and Liver Issues

Antibiotics rank high among the drugs that can cause liver damage. Researchers note that “fluoroquinolones are among the most widely prescribed antibiotic agents in North America.” As prescriptions for these drugs continue to climb, adverse effects have surfaced, such as hepatotoxicity, hemolysis, renal failure and serious events.

Of the quinolones, moxifloxacin (Avelox) has raised the most red flags; the European Medicines Agency voiced concerns about its causing potential hepatotoxicity (chemical-induced liver damage), and Health Canada issued warnings about the danger of moxifloxacin-associated liver damage.

However, there is a lack of research in this area. A desire to fill this gap is why Paterson and his team chose to look at quinolones and liver damage.

The Canadian research team noted that, “compared with clarithromycin, Avelox was associated with a more than two-fold increased risk of admission to hospital for acute liver injury (adjusted [odds ratio (OR)] 2.20, 95% [confidence interval (CI)] 1.21 – 3.98) [P = .009]. Levaquin was associated with a statistically significant but lower risk of hepatotoxicity than we saw with Avelox (adjusted OR 1.85, 95% CI 1.01–3.39) [P = .046].”

More Research Needs to Happen

Commenting on the findings, Dr. Adrian Reuben MBBS, FRCP, chief of the Liver Service, Division of Gastroenterology and Hepatology, Medical University of South Carolina, Charleston, notes that patients who need an antibiotic may be compromised in some way, and be more susceptible to drug toxicity or “the finding could be a result of the propensity of the fluoroquinolone family of drugs to cause injury with different family members injuring different organs.”

The study, authors acknowledge, is far from perfect. The administrative data used lacks information “about liver function, actual medication consumption, use of over-the-counter medicines, or cause of death.” Moreover, hospital admission records don’t show less severe cases of liver injury treated in other healthcare settings. And the drug’s impact on the elderly may not reflect younger patients’ reactions.

That said, Paterson and colleagues conclude that “Although our results require confirmation in other settings, they suggest that both moxifloxacin and levofloxacin be considered for regulatory warnings regarding acute liver injury.”