Invokana and Invokamet contain canagliflozin, a diabetes drug that hit the market in March 2013. It controls blood-sugar levels by forcing the body to remove more sugar in urine.
No one knows the long-term risks, but in only three years the FDA has warned about bone fractures, ketoacidosis, kidney failure, infections, sepsis — and now amputations.
The FDA is concerned about preliminary data from the CANVAS clinical trial, an ongoing study involving nearly 4,500 people with diabetes that began in 2009.
Patients were randomly assigned to take Invokana (100-mg or 300-mg) or a placebo every day. After one year, about 7 in 1,000 patients on Invokana needed an amputation compared to 3 in 1,000 patients on a placebo.
Janssen Pharmaceuticals, manufacturer of Invokana and Invokamet, warned doctors in Europe that dehydration and blood-volume depletion may play a role in the development of foot disease.
Dehydration is one of the most common side effects because Invokana and Invokamet cause excessive urination. The other problem is that diabetes is a major risk-factor for amputations.
About 15% of all diabetics develop foot ulcers at some point, and 25% of them need toe amputations. Diabetes hardens arteries, damages nerves in the feet, and causes poor circulation in the lower legs. Even minor cuts can rapidly get infected because sores do not heal very well.
Any medications that further increase the risk of amputations must be carefully considered by patients and their doctors. In the meantime, the FDA recommends:
Patients taking canaglifozin should notify their health care professionals right away if they notice any new pain or tenderness, sores or ulcers, or infections in their legs or feet.”
How to Prevent Diabetic Foot
How to Keep Your Feet Healthy:
- Check your feet every day
- Wash your feet every day
- Keep the skin soft and smooth
- Smooth corns and calluses gently
- If you can see, reach, and feel your feet, trim your toenails regularly. If you cannot, ask a foot doctor (podiatrist) to trim them for you.
- Wear shoes and socks at all times
- Protect your feet from hot and cold
- Keep the blood flowing to your feet
Do you have diabetes or know someone who does?