By Louise Gagnon

TORONTO, CANADA -- October 16, 2006 -- The development of hypoglycemia in elderly patients appears to be a side effect unique to gatifloxacin, and does not occur with other fluoroquinolone antibiotics, according to a prospective study presented here Saturday at the Infectious Diseases Society of America (IDSA).

Previous research established that hypoglycemia can occur in elderly patients who are treated with the antibiotic agent gatifloxacin, according to lead researcher Mark Decerbo PharmD, BCPS, assistant professor of pharmacy, University of Southern Nevada College of Pharmacy, Henderson, Nevada, University Medical Center of Southern Nevada, Las Vegas, Nevada.

To determine whether the effect of gatifloxacin is a class effect, Dr. Decerbo and colleagues enrolled patients who were 65 years and older and received antibiotic therapy at a 600-bed teaching hospital.

Patients were excluded from the study if their pretreatment blood glucose level was less than 60 mg/dL or unknown, if they received glucose-altering agents apart from insulin or sulfonylureas, had known or suspected renal insufficiency or insulin secreting tumor, had used antibiotics within the preceding 48 hours of enrolment, or had been admitted to the intensive care unit.

Hypoglycemia was defined as serum glucose level less than 60 mg/dL within a period of 48 hours after the first dose of antibiotics.

Traditional risk factors for hypoglycemia include age 65 years and greater, diabetes, renal dysfunction, and use of agents altering blood glucose levels.

A total of 79 patients received ciprofloxacin, 98 received levofloxacin, 92 received moxifloxacin; 227 patients who received non-fluoroquinolones served as control subjects.

Hypoglycemia developed in 2.5% of patients on ciprofloxacin, 4.1% of patients on levofloxacin, 2.2% of patients on moxifloxacin, and 1.8% on non-fluoroquinolone antibiotics.

Overall, 2.2% of patients on fluoroquinolones developed low blood sugar levels. There were no statistically significant differences in the development of hypoglycemia between patients who received the fluoroquinolones and those who did not, or in the development of the condition among patients receiving fluoroquinolones.

"The number of cases with levofloxacin was higher, which fits with the literature, but it was not significantly different from other agents," said Dr. Decerbo.

Investigators also analyzed the effect of diabetic status on the development of hypoglycemia, but found no increased risk of hypoglycemia according to diabetic status. Specifically, of patients taking fluoroquinolones, 4.3% of diabetics versus 2.7% of non-diabetics became hypoglycemic, yielding a P value of .92. Among controls, 6.1% of diabetics became hypoglycemic compared with 1.0% of nondiabetics, yielding a P value of .19.

Although the study was designed to detect the differences in the impact of the fluoroquinolone agents, a larger study may be needed with greater power to detect those differences, according to Dr. Decerbo.

"We may need closer to 1,000 patients to find differences between the agents," he said.

The study was independently conducted.

[Presentation title: Rate of Early-Onset Hypoglycemia Associated with Ciprofloxacin, Levofloxacin, and Moxifloxacin, versus Non-Fluoroquinolone Antibiotics in Elderly Patients. Poster 1077]

NOTE: This study is in direct contradiction of the research found on Med Watch as well as other leading medical publications.  Current research indeed shows hypo and hyperglycemic reactions are a class effect of the drugs found within the class commonly referred to as Fluoroquinolones/Quinolones.