An Invokana amputation warning regarding the drug’s dangerous side effects stems from results of two different clinical trials.

In May 2017, the U.S. Food and Drug Administration (FDA) ordered Invokana maker Johnson & Johnson to add a black box warning to the medication’s label regarding the risk of amputations.

The FDA’s black box warning is the federal agency’s most dire warning, reserved for medications and medical devices that have side effects that might cause severe injury or death, including the possibility of Invokana amputation. 

The two clinical trials looked at patients taking Invokana (canagliflozin), Invokamet and Invokamet XR.

The clinical trials, known as CANVAS (Canagliflozin Cardiovascular Assessment Study) and CANVAS-A (A Study of the Effects of Canagliflozin on Renal Endpoints in Adult Participants with Type 2 Diabetes Mellitus).

Patients who took Invokana, Invokamet or Invokamet XR experienced a need for leg and foot amputations at twice the rate as patients who were not treated with the medications.

Invokana Amputation Warning Medicine’s Newest Danger

The FDA’s Invokana amputation warning is the latest in a series of serious revelations regarding the drug’s potential side effects.

Approved by the FDA in 2014 to help control blood sugar in patients with type-2 diabetes, Invokana was the first drug in a new class of medications. Called SGLT2 inhibitors, the drugs work by eliminating excess sugar (glucose) by redirecting it through the kidneys and out the urine. Otherwise, the sugar would go back into the bloodstream.

A person with diabetes is already at greater risk of kidney complications. Invokana stresses the kidneys by sending sugar out through the urine. With increased urine production, Invokana patients can suffer dehydration, which further taxes the kidneys.

The FDA added a warning regarding the increased risk of acute kidney injury to the labels of SGLT2 inhibitors in 2016.

In 2015, the FDA added warnings that SGLT2 inhibitors could cause an increased risk of diabetic ketoacidosis, a potentially fatal condition marked by dehydration, insulin deficiency and an excess of blood acids known as ketones. That same year, a warning was added that patients taking SGLT2 inhibitors could develop urinary tract infections that progress to dangerous sepsis (blood infection) or kidney infections.

The Invokana amputation warning says the risk might be higher for patients who have peripheral vascular disease, neuropathy (nerve damage), or diabetic foot ulcers (sores), or those have needed a prior amputation.

In the CANVAS studies, amputations of the toe and middle of the foot were the most common, but some amputations involved the leg, below or above the knee. Some patients in the large clinical trials experienced more than one amputation, sometimes involving both limbs.

Johnson & Johnson and subsidiary Janssen Pharmaceuticals are facing hundreds of lawsuits from patients who allege they were not adequately warned of the potentially serious and damaging side effects of Invokana, Invokamet, and Invokamet XR.

If you or someone you love has taken an SGLT2 inhibitor and needed an amputation either before or after the Invokana amputation warning was issued, you could be eligible for compensation through legal representation.