The U.S. Food and Drug Administration (FDA) has recently asked the Johnson & Johnson Co. to step up its efforts to warn the public regarding the increased risk of Invokana limb amputation.

Invokana, a medication used to treat type-2 diabetes, is part of a class of drugs known as sodium-glucose cotransporter-2 (SGLT2) inhibitors. A growing number of patients report problems with Invokana limb amputation. 

Also included in this class are Jardiance, Farxiga, Invokamet, and Invokamet XR. The latter two contain the same active ingredient as Invokana—canaglifozin—with metformin, a more traditional diabetic medication.

The FDA is requiring a label change of Invokana, Invokamet, and Invokamet XR that includes a black box warning. Black box label warnings are reserved for drugs with the potential for very serious adverse side effects such as Invokana limb amputation. Recent clinical trials were completed that had monitored patients taking Invokana, Invokamet and Invokamet XR against a control group taking a pill without an active ingredient.

Upon conclusion of these trials and configuration of the results, it was found that those ingesting the SGLT2 inhibitors were twice as likely to have had to undergo Invokana limb amputation of toes, feet, and legs. The FDA sent out a safety announcement in May 2017 and posted the trial conclusions on its website.

Certain patients taking Invokana, Invokamet, and Invokamet XR have an increased risk of needing Invokana limb amputation by virtue of medical events and conditions existing prior to starting treatment. These medical conditions include neuropathy, peripheral vascular disease, previous amputations, and ulcerative conditions of the foot.

Early signs that a patient might be developing a problem that could lead to Invokana limb amputation might be new infections or ulcers in the feet, pain, and swelling. Patients that have been taking this drug should consult their physician if any of these symptoms are noticed.

In addition to Invokana limb amputation, Invokana, Invokamet, and Invokamet XR have been implicated in other life-threatening conditions leading to over two hundred filed lawsuits against the pharmaceutical giant, Johnson & Johnson. One of these serious alleged conditions is kidney failure.

Invokana works by inhibiting the body from reabsorbing extra glucose in the blood and directing it out through the body’s urine output. While a good idea theoretically, this inhibition of the reabsorption process puts extra strain on the kidneys which ultimately may prove dangerous in a certain percentage of takers.

Ketoacidosis, a condition in which the body’s fluids become highly acidic, has also been linked to taking SGLT2 inhibitors such as Invokana. The condition is created by the body producing acids known as ketones in excess. This often happens when a person goes a lengthy period of time without ingesting food or when insulin levels drop precipitously.

The relationship of SGLT2 inhibitors to ketoacidosis was warned about by the FDA in May 2015 in a separate safety announcement. Symptoms of ketoacidosis can include upset stomach, shortness of breath, throwing up, unexplained exhaustion, and a lack of mental clarity.