The U.S. Food and Drug Administration (FDA) confirms the popular Johnson & Johnson (J&J) diabetes drug Invokana (Invokamet, Invokamet XR) increases the risk of foot and leg amputations in people with Type 2 diabetes. 
The results of 2 clinical trials showed leg and foot amputations occurred about twice as often in patients taking Invokana (generic name: canagliflozin) as those given a placebo, according to an announcement on the FDA’s website. 
The nation’s health watchdog says it is requiring that new warnings, including its most prominent Boxed Warning, be added to the Invokana label.
One of the clinical trials indicated that over the course of a year, the risk of amputation in Invokana patients was about 9.5 out of 1,000, compared with 2.8 out of 1,000 for those in the placebo group.
In the second clinical trial, the results showed the risk of amputation was equivalent to 7.5 out of every 1,000 patients treated with Invokana, compared with 4.2 out of every 1,000 patients given a placebo.
The most common amputations involved the toe and middle of the foot; however, amputations involving the leg, below and above the knee, also occurred.
People taking Invokana are being urged by the FDA to contact their healthcare professional immediately if they experience new pain or tenderness, sores or ulcers, or infections in their legs or feet. However, patients should not stop taking the medication without first discussing it with their healthcare provider. (I feel like I’m in a commercial.) 
The FDA says that before prescribing Invokana for a patient with Type 2 diabetes, healthcare providers should take into account whether an individual has a history of prior amputation, or suffers from peripheral vascular disease, neuropathy, and diabetic foot ulcers, as these may increase the risk of amputation even more.
Foot and leg amputations are common complications of Type 2 diabetes. This is because many people with diabetes have blood vessel disease, which results in restricted blood flow to the lower extremities, along with nerve disease (neuropathy), which reduces sensation in the feet. 
The combination of problems often leads to sores and ulcers that the individual may not be able to feel. When a wound goes unnoticed, and thus goes untreated, it can lead to infections that are sometimes impossible to treat.
Amputation is not an unavoidable complication, fortunately. Routine foot care can prevent the need for such drastic measures.
Invokana belongs to a class of Type 2 diabetes drugs, known as SGLT-2 inhibitors, which help rid the body of excess blood sugar through urination. Other popular SGLT-2 inhibitors include Eli Lilly and Co’s Jardiance and AstraZeneca Plc’s Farxiga.
Sometimes the pharmaceutical drugs intended to keep blood sugar low and prevent devastating side effects and complications wind up doing more harm than good.
In 2014, a study found that a type of recombinant insulin intended for use in people with Type 2 diabetes may actually trigger Type 1 diabetes in patients.
Additionally, in 2016, the FDA issued warnings for diabetes medications containing saxagliptin and alogliptin, as the drugs were shown to increase the risk of heart failure, particularly in people who already have heart or kidney disease.