Aug. 30, 2018 -- The FDA is warning about rare cases of necrotizing fasciitis -- sometimes called “flesh-eating bacteria” -- of the genitals and genital area in patients taking type 2 diabetes drugs known as SGLT2 inhibitors.

The new warning will be added to the prescribing information and the patient medication guides for all types of the drugs and drug combinations approved to treat type 2 diabetes. They include:

Canagliflozin (Invokana, Invokamet, Invokamet XR)

Dapagliflozin (Farxiga, Xigduo XR, Qtern)

Empagliflozin (Jardiance, Glyxambi, Synjardy, Synjardy XR)

Ertugliflozin (Steglatro, Segluromet, Steglujan)

Necrotizing fasciitis of the genital area, also called Fournier's gangrene, is a life-threatening bacterial infection of the tissues under the skin surrounding the muscles, nerves, fat, and blood vessel in the genital area. It is estimated to happen to about 1.6 of 100,000 men annually in the United States, most often among those ages 50 to 79.

But from March 2013 to May 2018, the FDA received reports of 12 cases of Fournier's gangrene among patients taking SGLT2 inhibitors, of whom five were women and seven were men. The condition has rarely been reported among women. The patients ranged from 38 to 78 years old.

The condition developed an average of 9.2 months after the patients starting taking the drug. (Though the development time ranged from 7 days to 25 months.) Patients stopped taking the drug in most cases.