IDSA: Link Between Tequin (gatifloxacin) and Hypoglycemia Strengthened

By Rabiya Tuma, Ph.D., MedPage Today Staff Writer
Reviewed by Zalman S. Agus, MD; Emeritus Professor at the University of Pennsylvania School of Medicine.
October 11, 2005

This small and preliminary study supports a relationship between Tequin (gatifloxacin) and the development of hypoglycemia in older patients, especially if they have diabetes. Consider this association when selecting antibiotic therapy for elderly diabetic patients.

This study was published as an abstract and presented orally at a conference. These data and conclusions should be considered to be preliminary as they have not yet been reviewed and published in a peer-reviewed publication.

Review
SAN FRANCISCO, Oct. 11 - Treatment with the fluoroquinolone Tequin (gatifloxacin) was strongly associated with hypoglycemia in elderly patients, particularly those with diabetes, according to a prospective cohort study.

Of 196 elderly patients enrolled in the study, 77 were taking Tequin and 119 a non-quinolone antibiotic. Ten patients developed hypoglycemia after Tequin dosing, whereas only one case occurred in the non-quinolone group, researchers reported at a meeting here of the Infectious Disease Society of America.

The rate of hypoglycemia differed significantly between the groups, with 13% in the Tequin treatment arm becoming hypoglycemic compared with 0.8% in the non-quinolone group (P=.0004, relative risk 15.4, 95% CI 2.02 - 118.33), said the researchers.

"Right off the bat, even with a pretty small sample size, it reached the level of significance," said Mark C. Decerbo, Pharm.D. of the University of Southern Nevada in Henderson who presented the work. Dr. Decerbo noted earlier anecdotal reports of the hypoglycemia connection.

In addition, diabetes significantly increased the risk of hypoglycemia in patients treated with Tequin (P=.01). Of 22 diabetic patients given Tequin, seven (31.8%) became hypoglycemic, compared with only three of 55 (5.5%) nondiabetic patients (p=.004, RR 5.8, 95% CI 1.66-20.54).

The risk tended to increase even more for those diabetic patients on scheduled insulin therapy or on sulfonylurea drugs compared with those not on prescription therapy, although the risk did not reach significance (p=1.00, RR 1.82, 95% CI, 0.46-7.11).

In addition to diabetes, various other factors were predictors of hypoglycemia, including age, renal function, sepsis, hypoalbuminemia, liver disease, malignancy, and cardiac heart failure.

"Not all fluoroquinolones are created equal," Dr. Decerbo said. Other adverse effects -- skin rashes, for example -- have been seen with individual fluoroquinolones, he noted, but suggested that hypoglycemia looks like a "predominantly Tequin-specific effect."

Additionally, the researchers said that because more blood samples were collected from the diabetic patients than from the non-diabetics, some hypoglycemia might have been missed in the non-diabetics patients.

Given that anecdotal evidence, including previous voluntary reports to the FDA suggesting that Tequin can trigger dysglycemic events, one audience member asked how the research team got this protocol approved by its hospital's IRB.

The board had discussed the matter, Dr. Decerbo said, and was aware of the anecdotal information. Nevertheless, the board concluded that without prospective information, there wasn't sufficient evidence to be sure of the link. "Now there is," Dr. Decerbo said. The hospital has since changed its formulary to reflect the results of the study.

Primary source: Infectious Disease Society of America Meeting
Source reference:
Greenberg, MD. Rate of Early-Onset Hypoglycemia Associated with Gatifloxacin versus non-fluoroquinolone antibiotics in elderly patients. Infectious Disease Society of America Meeting 2005.