The US Food and Drug Administration (FDA) has strengthened warnings for the fluoroquinolone class of antibiotics after they were found to cause mental health problems and serious blood sugar disturbances, including hypoglycaemic coma in people with diabetes. Fluoroquinolones include ciprofloxacin, levofloxacin, moxifloxacin , ofloxacin, gemifloxacin and delafloxacin, which are used to treat common bacterial infections,