Researchers have found that, compared with other antibiotics, people with diabetes taking a class known as fluoroquinolones may be at higher risk of blood sugar-related complications.

Researchers from National Taiwan University in Taipei, carried out a population-based cohort study of around 78,000 people with diabetes.

The researchers analyzed data from the claims database for Taiwan’s national insurance program, and looked at patients who had received an oral prescription of one of these three different classes of antibiotics: fluoroquinolones (levofloxacin, ciprofloxacin or moxifloxacin), second-generation cephalosporins (cefuroxime, cefaclor or cefprozil), acrolides (clarithromycin or azithromycin).

The scientists analyzed the number of emergency visits and hospitalizations related to diabetes within 30 days of the patients using the antibiotics. The visits were for dysglycemia, with blood sugars either too high (hyperglycemia) or too low (hypoglycemia).

The study, published in the journal Clinical Infectious Diseases, revealed that the patients with diabetes using fluoroquinolones had a higher risk of dysglycemia than the diabetics using other antibiotics.

The research showed that the risk was dependent on the type of antibiotic the patient was using within the class of fluoroquinolones.

The incidence, or absolute risk, of hyperglycemia cases for every 1,000 people was:

  • Moxifloxacin – 6.9
  • Ciprofloxacin – 4.0
  • Levofloxacin – 3.9.

The absolute risk of hypoglycemia cases per every 1,000 people was:

  • Moxifloxacin – 10.0
  • Levofloxacin – 9.3
  • Ciprofloxacin – 7.9.

Fluoroquinolones are a class of antibiotics with a wide number of uses against bacterial infection.

By comparison, the researchers found the absolute risks were lower among diabetes patients taking other antibiotics that can be used. The numbers were:

  • In the macrolides class: 1.6 per 1,000 (hyperglycemia), 3.7 (hypo)
  • For cephalosporin antibiotics: 2.1 per 1,000 (hyperglycemia), 3.2 (hypo).

The researchers say that previous research has linked fluoroquinolones to dysglycemia. They note that one of the fluoroquinolone antibiotics, gatifloxacin, was withdrawn from the US market in 2006 due, the researchers say, “to the risk of blood sugar abnormalities.”

The study authors conclude that this research should prompt clinicians to consider the risks when prescribing fluoroquinolones for diabetes patients. They authors say:

Our results showed a class effect regarding increased risk of severe dysglycemia among diabetic patients administered fluoroquinolones in Taiwan.”

“Clinicians should consider these risks when treating patients with diabetes and prescribe fluoroquinolones cautiously.”

People with diabetes can spot hypoglycemia early. Low blood sugar can, however, become serious, as listed by the Mayo Clinic: clumsiness or jerky movements, muscle weakness, difficulty speaking or slurred speech, blurry or double vision, drowsiness, confusion, convulsions or seizures, and unconsciousness.

High blood sugars, hyperglycemia, can “become severe and lead to serious complications requiring emergency care, such as diabetic coma.”