A new nationwide cohort study has shown that patients with diabetes who use oral fluoroquinolone antibiotics are at greater risk for severe dysglycemia than those using other antibiotics.

And although the risk was low — hyperglycemia or hypoglycemia related to fluoroquinolones occurred in fewer than 1 in 100 patients studied in the trial in 78,000 diabetics — doctors should still exercise caution, say Hsu-Wen Chou, MS, from the National Taiwan University, Taipei, and colleagues in their paper published onlineAugust 15 in Clinical Infectious Diseases.

The risks also appear to vary according to the type of fluoroquinolone antibiotic used, and 1 in particular, moxifloxacin (Avelox, Bayer), appears to most increase the likelihood of hypoglycemia, an effect that is heightened among patients receiving concomitant insulin or sulfonylurea treatment, coauthor Wang Jiun-Ling, MD, from I-Shou University and E-Da Hospital, Kaohsiung, Taiwan, told Medscape Medical News.

“Clinicians should consider hypoglycemic risks when treating diabetic patients with infection and prescribe fluoroquinolones cautiously,” said Dr. Wang. “If patients have a higher risk of hypoglycemia or develop hyper- or hypoglycemia during fluoroquinolone use, another class of antibiotic — such as beta-lactam or macrolide — should be considered.”

And patients should also be made aware of the risks, he added. “Those with diabetes who need to take fluoroquinolones should better understand the signs and symptoms of hypoglycemia and check blood glucose where necessary.”

Those With Renal Disease Also at Greater Risk

Dr. Chou and colleagues explain in their paper that fluoroquinolones, used to treat urinary-tract infections and community-acquired pneumonia among other things, are being increasingly prescribed because of their broad spectrum of action. But this greater use has spawned concerns regarding rare but severe adverse effects, which include tendon rupture, QT-interval prolongation, and dysglycemia.

In fact, one fluoroquinolone antibiotic, gatifloxacin (Tequin, Bristol-Myers Squibb), was already withdrawn from the US market in 2006 due to the risk for severe dysglycemia. However, there are insufficient data describing the likelihood of dysglycemia with other fluoroquinolones, they say.

Using the claims database for Taiwan’s national insurance program, the researchers analyzed data from 78,433 outpatients with mostly type 2 diabetes who had received a new prescription for an antibiotic from January 2006 to November 2007.

The antibiotics were divided into 3 classes: fluoroquinolones (levofloxacin, ciprofloxacin, or moxifloxacin); second-generation cephalosporins (cefuroxime, cefaclor, or cefprozil); or macrolides (clarithromycin or azithromycin).

A “study event” was defined as an emergency-department visit or hospitalization for dysglycemia among these patients within 30 days of the start of their antibiotic therapy.

Diabetic patients using oral fluoroquinolones faced greater risk for severe dysglycemia than those using antibiotics in other classes.

After multinomial propensity score adjustment, the odds ratio for hyperglycemia was 1.75 for levofloxacin, 1.87 for ciprofloxacin, and 2.48 for moxifloxacin compared with use of macrolides.

For hypoglycemia, the adjusted odds ratios (AORs) were 1.79, 1.46, and 2.13 for the same drugs, respectively, compared with macrolides.

This adverse effect was also more likely to occur in patients who suffered from comorbid kidney disease as well as those who were concomitantly treated with insulin or sulfonylureas, the researchers note.

“Our results showed a class effect regarding increased risk of severe dysglycemia among diabetic patients administered fluoroquinolones in Taiwan. Hypoglycemic risk varied according to the specifics of each drug and was most commonly associated with moxifloxacin. Clinicians should consider these risks when treating patients with diabetes and prescribe fluoroquinolones cautiously,” they conclude.

Sourrce: Medscape.com

Source: http://www.sciencedirect.com