Type-2 Diabetes patients take heed: brand name diabetes drugs Invokana, Invokamet, and Invokamet XR must now include a new safety label warning about the increased risk of foot and leg amputations while taking the drug, according to the FDA.

Last summer, the FDA issued a Safety Communication warning patients of the increased risk of foot and leg amputations taking Canagliflozin, a sodium-glucose cotransporter-2 (SGLT2) inhibitor, and sold under brand names Invokana, Invokamet, and Invokamet XR. These drugs are prescribed to adults suffering from type-2 diabetes to help lower blood sugar.

The Safety Communication in June 2016 was issued after clinical trial results showed patients who took the drug for at least 4.5 years had twice as many foot and leg amputations as patients taking a placebo. The FDA stopped short of requiring drug makers to change their safety labels to warn of the amputation risk but advised at that time it would conduct additional safety testing to investigate the increased risk, and issue additional information to the public.

After two large clinical trials confirmed patients taking Canagliflozin did in fact experience twice as many foot and leg amputations as patients taking a placebo, the FDA is now ordering drug makers to include a prominent black box warning on all Canagliflozin products, the most serious safety warning required by the FDA. Clinical trials showed amputations of the toes and middle foot were the most common type of amputations, although some patients required leg amputation above or below the knee, and some required amputation on both limbs.

If you have type-2 diabetes and are taking Canagliflozin, the FDA advises:

  • Despite the risk, DO NOT stop taking the drug without first speaking with your prescribing doctor.
  • Immediately advise your doctor if you begin to experience any new pain or tenderness, ulcers, sores or infection in the feet or legs.

The FDA strongly urges prescribing doctors to:

  • Talk to patients about their history of prior amputation, vascular disease, diabetic foot ulcers and neuropathy to determine if they may have a pre-disposition to amputation.
  • Closely monitor any patients taking the drug, and discontinue the drug immediately if any new symptoms of pain, tenderness, ulcers, sores or infection occur in the feet or legs.

As with any drug, the FDA asks patients and doctors to report any side effects or adverse events when taking Canagliflozin by filing a MedWatch report with the FDA, or calling the FDA at 1-800-332-1088. Reports can be filed at https://www.accessdata.fda.gov/scripts/medwatch/.