Fluoroquinolone Impact on Mental Health and Blood Sugars

Sara Massey, Pharm.D, Smiley’s Family Medicine Clinic

Fluoroquinolone antibiotics are used to treat many serious bacterial infections, including some bacterial pneumonias.  Previously, the Food and Drug Administration (FDA) has associated an increased risk of tendon rupture, tendonitis, and peripheral neuropathy with the use of fluoroquinolones.  The FDA is now requiring additional risks be added to the labels and patient Medication Guides of all brand and generic fluoroquinolones (levofloxacin, ciprofloxacin, moxifloxacin, ofloxacin, gemifloxacin, and delafloxacin).  

In July 2018, the U.S. FDA released a statement regarding the safety of fluoroquinolones, which included an increased risk of mental health side effects and changes in blood glucose.  Associated mental health side effects include attention disturbances, disorientation, agitation, nervousness, memory impairment, and delirium. Warnings and precautions about central nervous system changes associated with various fluoroquinolones were previously described on their labels, however this new warning makes mental health risks more prominent and will apply to all fluoroquinolones.  Blood sugar disturbances due to fluoroquinolones have already been established by the FDA; however, the FDA is now expanding the warning to include the risk of hypoglycemia which can lead to life-threatening coma. Elderly patients and/or patients taking oral hypoglycemic medications or insulin are at much higher risk of developing hypoglycemia or coma due to fluoroquinolone use than the general public.

As healthcare professionals, it is important to understand the new risks associated with fluoroquinolones.  This new information can be important in determining the best antibiotic for patients, especially the elderly, those with mental health disease, and those with diabetes at a high risk for hypoglycemia. Fluoroquinolones have a valid place in therapy and should be considered for treatment as long as the risk and benefits are evaluated for each individual patient.


1. FDA news release: FDA updates warnings for fluoroquinolone antibiotics on risks of mental health and low blood sugar adverse reactions. U.S. Food and Drug Administration. https://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm612995.htm. Published July 10, 2018.

2. FDA safety announcement: FDA reinforces safety information about serious low blood sugar levels and mental health side effects with fluoroquinolone antibiotics; requires label changes. U.S. Food and Drug Administration. https://www.fda.gov/Drugs/DrugSafety/ucm611032.htm. Published July 10, 2018.