The U.S. Food and Drug Administration is requiring prominent new boxed warnings on the type 2 diabetes drug canagliflozin after two studies found it presents an increased risk of leg and foot amputations. The drug is sold under the brand names Invokana, Invokamet, and Invokamet XR.
The FDA said that patients taking the drug should notify their health care professionals right away if they develop new pain or tenderness, sores or ulcers, or infections in the legs or feet. Talk to your health care professional if you have questions or concerns. Do not stop taking your diabetes medicine without first talking to your health care professional.
Health care professionals should, before starting canagliflozin, consider factors that may predispose patients to the need for amputations. These factors include a history of prior amputation, peripheral vascular disease, neuropathy, and diabetic foot ulcers.
Final results from two clinical trials – the CANVAS (Canagliflozin Cardiovascular Assessment Study) and CANVAS-R (A Study of the Effects of Canagliflozin on Renal Endpoints in Adult Participants With Type 2 Diabetes Mellitus) – showed that leg and foot amputations occurred about twice as often in patients treated with canagliflozin compared to patients treated with placebo, which is an inactive treatment.
Canagliflozin is a prescription medicine used with diet and exercise to lower blood sugar in adults with type 2 diabetes. It belongs to a class of drugs called sodium-glucose cotransporter-2 (SGLT2) inhibitors. Canagliflozin lowers blood sugar by causing the kidneys to remove sugar from the body through the urine.
The heightened warning follows a May 2016 safety alert based on interim data from one of two ongoing trials. Now, final results from both trials indicate an approximate doubling of the risk for both leg and foot amputations in canagliflozin-treated patients compared to those randomly assigned to receive placebo.