In 2013, the FDA approved a new type of drug to help those suffering from type 2 diabetes manage their blood sugar levels. Invokana (canagliflozin), is an SGLT2 Inhibitor (sodium glucose co-transporter 2) that works in a totally different way than past medications designed to help diabetics. When blood is filtered through the kidneys, it removes glucose and then later redistributes it through the blood again. SGLT2 inhibitors block the reabsorption of the glucose into the blood and instead release it out of the body through urine.
Diabetes can cause several complications in the body, which may include neuropathy. Neuropathy is when your nerves get inflamed and start to degenerate which leads to poor circulation and and nerve damage. Neuropathy occurs in 60 percent to 70 percent of patients who have diabetes and causes numbness, tingling, and loss of feeling mainly in the legs and feet. Unfortunately, when feeling is lost in these appendages, sores and ulcers may form without a person knowing they’re there. Since circulation is hindered because of the nerve damage, the wound can’t heal properly and often gets worse. If a patient doesn’t get treatment immediately, the wound can become infected, the infection can spread to surrounding tissue, and then the only way to address the sick tissue may be through amputation.
On May 16, 2017, the FDA released a Safety Communication which said, “Based on new data from two large clinical trials, the U.S. Food and Drug Administration (FDA) has concluded that the type 2 diabetes medicine canagliflozin (Invokana, Invokamet, Invokamet XR) causes an increased risk of leg and foot amputations. We are requiring new warnings, including our most prominent Boxed Warning, to be added to the canagliflozin drug labels to describe this risk.”
The studies mentioned in this FDA warning are called 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). Here is the important information that these clinical studies found:
Over a year’s time, the risk of amputation for patients in the trial were equivalent to:
The CANVAS-R trial showed that over a year’s time, the risk of amputation for patients in the trial were equivalent to:
This means that people who used a canagliflozin like Invokana were almost twice as likely to have one or more amputations. Toe and middle foot amputations were the most common, but below and above the knee leg amputations were also reported. Furthermore, some patients reported having multiple amputations, “some involving both limbs.”
