Some Antibiotics Linked to Kidney InjuryJun 5, 2013
A recent study has found that men taking antibiotic medications in the class known as fluoroquinolone—Cipro (ciprofloxacin), Levaquin (levofloxacin), and Avelox (moxifloxacin)—experience a twofold risk of also suffering significant kidney problems, compared to men not taking the drugs.
The study also revealed that men aged 40 to 85 who were taking a fluoroquinolone and an ACE inhibitor for blood pressure experienced a fivefold increased risk for kidney problems, according to Reuters Health.
Fluoroquinolones work on a broad spectrum of bacteria, including in the intestinal and urinary tracts and the respiratory system, according to Reuters Health. The powerful antibiotics are typically prescribed when other medications have failed.
Fluoroquinolones' known potential side effects include irregular heartbeat, insomnia, and allergic reactions; kidney failure is indicated as a rare event. Because of this, physicians typically do not take this side effect into account, says the United States and Canadian team that published the findings in the Canadian Medical Association Journal, according to Reuters Health.
The researchers compared 1,292 men who were hospitalized with acute kidney injuries to 12,651 similar men who were hospitalized without that diagnosis and reviewed which had recently taken or were taking a fluoroquinolone drug. Eight percent of the men diagnosed with kidney injury were taking the drugs when admitted to the hospital compared to half that amount in the other group. Also, according to Reuters Health, one in 1,500 people given a fluoroquinolone suffered from acute kidney injury, which was twice the number of those in the group not taking the medication.
Some 40 million prescriptions for fluoroquinolones are dispensed in the United States each year, said one of the study’s authors, Mahyar Etminan of the University of British Columbia in Vancouver. This may be more than is needed, given that fluoroquinolones are sometimes prescribed when other, safer antibiotics would work as well, or when a patient has a virus, according to Reuters Health. "Older men who may have failed on other antibiotics and have a serious infection may require this, but most men (or women) probably don't need to be put on these antibiotics" until safer options have been tried, Etminan added.
This is not the first time that researchers have warned that fluoroquinolones should only be used in serious, even life-threatening, infections, such as hospital-acquired pneumonia. The drugs, however, are routinely prescribed for viruses, which do not respond to antibiotic treatment, or for infections that can resolve without medication, with less potent medication, or with nondrug treatments. Of note, while Levaquin was the best selling antibiotic in the United States in 2010, it was also the focus of more than 2,000 lawsuits in 2011.
We’ve also written that Avelox and Levaquin have been linked to liver injury in the elderly and that fluoroquinolone antibiotics are also associated with severe tendon injuries, including tendon rupture and tendonitis. Such injuries can occur while taking the antibiotic, or months after a prescription has been finished. Fluoroquinolone use may result in other rare but severe and even life-threatening side effects that involve swelling of the throat and/or face, difficulty swallowing, shortness of breath, rapid heartbeat, tingling in the toes or fingers, hives or itching, and loss of consciousness.
The drugs have also been linked to detached retinal problems and Health Canada has warned that people with myasthenia gravis should avoid fluoroquinolone antibiotics because they could worsen the rare, chronic disease that causes progressive muscle weakness, including in the eye and face muscles, neck and throat muscles, and limb muscles. Another study found that Zithromax may increase risks for death, specifically in patients with heart disease. Fluoroquinolones have also been linked to serious antibiotic-resistant infections, and one study blamed fluoroquinolones for 55 percent of C. difficile infections at one Quebec hospital.
In 2008, the U.S. Food & Drug Administration (FDA) required that the labeling of fluoroquinolone antibiotics be revised to include a black box warning about tendon injuries. When the FDA announced the black box warning, the agency’s database revealed 262 reported cases of tendon ruptures, 259 cases of tendonitis, and 274 cases of other tendon disorders associated with these drugs. The majority of tendon ruptures—61 percent—were tied to Levaquin.