The newer class of type 2 diabetes drugs—sodium-glucose cotransporter-2 inhibitors (SGLT2 inhibitors)—is under scrutiny as new information about SGLT2 inhibitor side effects emerges.
The SGLT2 class includes Invokana (canagliflozin), Farxiga (dapagliflozin) and Jardiance (empagliflozin), and Glyxambi, an empagliflozin-linagliptin combination.
SGLT2 inhibitors help control blood sugar in patients with type 2 diabetes by getting the kidneys to extract sugar from the blood and eliminate it through urination. The Food and Drug Administration (FDA) has approved SGLT2 inhibitors for the treatment of type 2 diabetes. SGLT2 inhibitors have not been formally evaluated as a treatment for type 1 diabetes.
In May 2015, the Food and Drug Administration (FDA) directed the manufacturers of Invokana and other SGLT2 inhibitors to amend the warning labels to list the risk of ketoacidosis.
Diabetic ketoacidosis is a life-threatening condition that develops when the body is unable to get the sugar (glucose) needed for energy because the body does not have enough insulin, the hormone that controls blood sugar. When the cells cannot get sugar for energy, the body begins to break down fat and muscle for energy and ketones (fatty acids) are produced. Ketones enter the bloodstream, causing the chemical imbalance diabetic ketoacidosis, WebMD explains.
Ketoacidosis is a known risk for diabetes patients, though it is typically a complication of type 1 diabetes rather than type 2. Ketoacidosis usually occurs in the presence of higher than normal blood sugar levels.
The FDA followed the May 2015 warning with a December 2015 order for a label change for Invokana and other SGLT2 inhibitors. The new label will describe the risk of ketoacidosis and give prescribing and monitoring recommendations. Manufacturers will also be required to conduct a post-marketing study, analyzing side effect reports and following up with patients over the course of five years.
The label change were prompted by the FDA’s review adverse event reports: there were 73 ketoacidosis reports from March 2013 to May 2015 in patients being treated with SGLT2 inhibitors. Because this reporting is voluntary, the FDA notes that there may have been ketoacidosis cases that went unreported during that time period
The FDA now recommends that patients stop taking an SGLT2 inhibitor immediately and seek medical attention if they experience any symptoms of ketoacidosis. Symptoms can include “nausea, vomiting, abdominal pain, tiredness, and trouble breathing,” the FDA says.
The FDA’s December 2015 safety announcement also noted other serious side effects experienced by SGLT2 inhibitor users. Between March 2013 and October 2014, the agency received 19 reports of urinary tract infections that developed into either life-threatening blood infections or kidney infections. These cases all required hospitalizations and some of the patients developed kidney failure requiring dialysis or intensive care treatment.
Other SGLT2 inhibitor side effects include dehydration, yeast infections and increased blood cholesterol. SGLT2 inhibitors can also lead to low blood sugar when used in combination with other diabetes medications.