FDA Alerts

Fluoroquinolones: Low Blood Sugar and Mental Health Adverse Effects

Fluoroquinolone antibiotics are approved to treat certain serious bacterial infections, and have been used for more than 30 years. They work by killing or stopping the growth of bacteria that can cause illness. Without treatment, some infections can spread and lead to serious health problems.

Most fluoroquinolone antibiotic drug labels include a warning that blood sugar disturbances, including high blood sugar and low blood sugar. Also, depending on the fluoroquinolone antibiotic class, a range of mental health side effects are already described under Central Nervous System Effects in the Warnings and Precautions section of the drug label.

The new label changes will add that low blood sugar levels can lead to coma. The new label will also make the mental health side effects more prominent and more consistent across the systemic fluoroquinolone drug class. The mental health side effects to be added to or updated across all the fluoroquinolones are:

  • Disturbances in attention
  • Disorientation
  • Agitation
  • Nervousness
  • Memory impairment
  • Serious disturbances in mental abilities called delirium

Recommendations for healthcare practitioners

  • Be aware of the potential risk of hypoglycemia sometimes resulting in coma, occurring more frequently in the elderly and those with diabetes taking an oral hypoglycemic medicine or insulin.
  • Alert patients of the symptoms of hypoglycemia and carefully monitor blood glucose levels in these patients. Discuss with them how to treat themselves if they have symptoms of hypoglycemia.
  • Inform patients about the risk of psychiatric adverse reactions that can occur after just one dose.
  • Stop fluoroquinolone treatment immediately if a patient reports any central nervous system side effects, including psychiatric adverse reactions, or blood glucose disturbances and switch to a non-fluoroquinolone antibiotic if possible.
  • Stop fluoroquinolone treatment immediately if a patient reports serious side effects involving the tendons, muscles, joints, or nerves, and switch to a non-fluoroquinolone antibiotic to complete the patient’s treatment course.
  • Avoid prescribing fluoroquinolones to patients who have other treatment options for acute bacterial sinusitis, acute bacterial exacerbation of chronic bronchitis, and uncomplicated urinary tract infections because the risks outweigh the benefits in these patients.

Recommendations for patients

  • Tell your healthcare professionals if you are taking a diabetes medicine when your healthcare professional is considering prescribing an antibiotic.
  • Tell your healthcare professionals if you have low blood sugar or symptoms of it while taking a fluoroquinolone. Early signs and symptoms of low blood sugar include:
    • confusion
    • pounding heart or very fast pulse
    • dizziness
    • pale skin
    • feeling shaky
    • sweating
    • unusual hunger
    • trembling
    • headaches
    • weakness
    • irritability
    • unusual anxiety

For patients with diabetes, your healthcare professional may ask you to check your blood sugar more often while taking a fluoroquinolone.

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