Quinolones may cause severe blood sugar swings

Diabetic patients taking oral fluoroquinolones were found to have a higher risk of severe blood sugar-related problems than diabetic patients taking other kinds of antibiotics, according to a recently published study.

The increased risk was low-hyperglycemia or hypoglycemia related to the drugs occurred in less than 1% of patients studied-but clinicians should consider the higher risk when treating diabetic patients with fluoroquinolones, especially moxifloxacin (Avelox), and prescribe them cautiously, the study’s authors concluded.

Fluoroquinolones, commonly used to treat urinary tract infections and other infectious diseases, have raised concerns about rare but severe adverse effects, including tendon rupture and arrhythmias. Previous studies have also indicated a relationship between the drugs and severe glucose-related abnormalities. In 2006, the fluoroquinolone gatifloxacin was withdrawn from the U.S. market due to the risk of blood sugar abnormalities.

Last week, the FDA required that the drug labels and medication guides for all oral and injectable fluoroquinolones be updated to better describe the serious side effect of peripheral neuropathy. This effect may occur soon after these drugs are taken and may be permanent.

To assess the risk of blood sugar swings in diabetic patients using specific fluoroquinolones, researchers led by Mei-Shu Lai, MD, PhD, at National Taiwan University in Taipei, conducted a population-based cohort study of approximately 78,000 people with diabetes in Taiwan from January 2006 to November 2007.

Using the claims database for Taiwan’s national insurance program, the researchers analyzed data for diabetic outpatients who had received a new prescription for an antibiotic from one of three different classes of antibiotics: fluoroquinolones (levofloxacin [Levaquin], ciprofloxacin [Cipro, Proquin], or moxifloxacin); second-generation cephalosporins (cefuroxime [Ceftin], cefaclor [Ceclor], or cefprozil [Cefzil]); or macrolides (clarithromycin [Biaxin] or azithromycin [Zithromax]). The study’s authors then looked for any emergency department visits or hospitalizations for dysglycemia among these patients within 30 days of the start of their antibiotic therapy.

Diabetics using oral fluoroquinolones faced greater risk of severe blood sugar swings than diabetic patients using antibiotics in other classes, the researchers reported online in Clinical Infectious Diseases (Aug. 14, 2013). The risks varied according to the specific fluoroquinolone the patients were using. The absolute risk of hyperglycemia per 1,000 people studied was 6.9 for moxifloxacin, 3.9 for levofloxacin, and 4.0 for ciprofloxacin. The absolute risk of hypoglycemia was 10.0 for moxifloxacin, 9.3 for levofloxacin, and 7.9 for ciprofloxacin.

“Our results identified moxifloxacin as the drug associated with the highest risk of hypoglycemia, followed by levofloxacin and ciprofloxacin,” the study’s authors wrote. “Other antibiotics should be considered if dysglycemia is a concern, such as a beta lactam or macrolide,” noted Dr. Lai.

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