Antibiotics Linked to Lows in People Taking Certain Diabetes Drugs

A new study from researchers at the University of Texas has linked certain antibiotics to hypoglycemia (low blood glucose) in older people taking sulfonylureas, a class of oral diabetes medicine prescribed to treat Type 2 diabetes. An estimated 26 million people in the United States have Type 2 diabetes.

To determine the risk of hypoglycemia in older people taking the diabetes medicines glipizide (brand name Glucotrol) or glyburide (DiaBeta, Glynase, PresTab, Micronase) along with one of 16 commonly prescribed antibiotics, the investigators looked at Texas Medicare claims covering the period from 2006 to 2009 for people at least 66 years old.


In those who had been prescribed one of the antibiotics included in the study, the rate of hypoglycemic episodes ranged from 0.17% to 1.44% in people taking glipizide and from 0.32% to 1.87% in people taking glyburide. The antibiotics ciprofloxacin (Cipro, Cipro XR, Proquin XR), clarithromycin (Biaxin, Biaxin XL), levofloxacin (Levaquin), metronidazole (Flagyl), and sulfamethoxazole-trimethoprim (Bactrim, Septra) were found to have a significant association with hypoglycemia.

Moxifloxacin (Avelox) and fluconazole (Diflucan), two antibiotics that previously appeared to be linked to hypoglycemia, were not found to have a significant association with lows in this study.

“Physicians should definitely avoid using those antibiotics in patients on sulfonylureas. In the great majority of cases, there are equally effective, noninteracting antibiotics available,” noted study author James S. Goodwin, MD, in an interview with Reuters Health. “In addition, antibiotics tend to be overprescribed in the community, so often the best choice is not to prescribe one. Some physicians may have the attitude of ‘well, it can’t hurt,’ when prescribing an antibiotic. Our study is an example of one of the many ways in which such drugs can hurt.”

Gerry Rayman, MD, FRCP, who was not involved with the research, added that if a hypoglycemia-associated antibiotic must be used in a person taking a sulfonylurea, that person should monitor his blood glucose levels more frequently.

For more information, read the article “Several antibiotics tied to hypoglycemia in patients on sulfonylureas” or see the study’s abstract in the journal JAMA Internal Medicine. And to learn more about preventing hypoglycemia, read the article “Take a Bite Out of Hypoglycemia: 10 Proven Strategies for Cutting Down on Low Blood Glucose,” by certified diabetes educator Gary Scheiner.

  • dora

    I have known this for years .I am insulin dependent.Everytime i take cipro or bactrim my blood sugar drops.I always ask the doctor why and they can not tell me.

  • Diane

    If we take insulin we need to get Medicare to give us more than three strips a day for testing! Control testing, spoiling one once inawhile, too much stress, sickness, and a host of other things plays havoc with the glucose. We need to get together and make them provide more than three strips. If obamacare can give free birthcontrol to the young, the old deserve more than three strips a day. For those of us who want tight control it is impossible on only three strips a day. Does anyone know what we can do?

  • margaret

    I too have known that antibiotics can make my glucose level go very low. I have type 2 diabetes. My problem is I am allergic to most antibiotics. My endocrinologist warned me about the lows. When I must take the medication I just test more often.

  • Cynthia

    Hi Diane,
    Ask your health care provider to write a “letter of medical necessity” saying that you need to test more than 3 times a day. Sometimes it works and sometimes it doesn’t, but it is something to try. You are absolutely right. You must test your blood glucose to be able to self-manage your diabetes and Medicare does not take into account the things you mention that can easily use up strips very quickly. Good luck!

  • Ira Weiss

    I took one of those antibiotics and the drop in blood sugars was dramatic during the course of treatment with some hypoglycemia. I even asked my endocrinologist if anyone had investigated using antibiotics as a diabetic treatment.

  • sam

    I find myself lucky to come across this antibiotics blog and read it. This blog is very informative.

  • john walker

    Most of the people are unaware this news that antibiotics
    are linked with the low blood sugar level. There are many risk
    and complications of diabetes
    . Medically this condition is well known
    as hypoglycemia which is strongly linked with the certain antibiotics.