Invokana is one of several “new generation” diabetes drugs that, along with Farxiga and Jardiance, make up a class of medications called SGLT2 inhibitors. While many sources have hailed these drugs as a “revolution” in type 2 diabetes management, SGLT2 inhibitors have already been linked to a severe side effect, ketoacidosis, in which elevated blood acid levels literally poison the body.
In a series of recent safety warnings, the Food & Drug Administration cautioned patients taking Invokana to watch for symptoms of the potentially fatal condition, going so far as to revise the drug’s label with a stronger warning.
Does Invokana Cause Kidney Failure?
While ketoacidosis has been the focus of concern for many patients, the FDA also warned of an apparent association between Invokana and abnormally severe urinary tract infections, saying, in no uncertain terms, “treatment with SGLT2 inhibitors increases the risk for urinary tract infections.”
In its review of adverse event reports, the agency identified at least 19 cases of “life-threatening blood infections (urosepsis) and kidney infections (pyelonephritis).” These infections, the announcement states, began as urinary tract infections then spread, either into a patient’s blood or to their kidney. All of the patients required hospitalization, “and a few required admission to an intensive care unit or dialysis in order to treat kidney failure.”
Kidney Risks Observed Nearly 2 Years Ago
While this newly confirmed risk may be shocking, it is not entirely unprecedented. Invokana was approved by the FDA on March 29, 2013, the first SGLT2 inhibitor to reach the US market. Even at this early stage, independent medical researchers had identified Invokana’s potential link to kidney problems. According to QuarterWatch, a nonprofit group monitoring serious adverse event reports, Invokana’s first year of sales was accompanied by numerous “serious injuries involving kidney function.”
Alarmed by these reports, QuarterWatch dug deeper, analyzing adverse event reports submitted to the FDA between April and June of 2014. Eventually, their search would identify 457 individual adverse event reports involving patients prescribed Invokana. In the same period, a total of 426,859 outpatient prescriptions were written for Invokana. In other words, we can estimate that for every 100 prescriptions written, 1 patient suffered a serious adverse event.
An abnormally high proportion of these reports involved “renal,” or kidney, function, which led QuarterWatch to identify Invokana’s active ingredient, canagliflozin, as a kidney toxin. The organization found:
- 54 reports of kidney failure or impairment
- 54 reports of dehydration and fluid imbalances
- 11 reports of kidney stones
- 50 reports of urinary tract infections
- 52 reports of abnormal or other weight loss
QuarterWatch’s conclusion was stated in no uncertain terms: these “5 different adverse effects
With these results in hand, the watchdog group questioned Invokana’s very safety, asking whether or not the drug’s purported benefits truly outweighed its potential risks.
QuarterWatch also raised doubts over Invokana’s benefits. Pointing out that the efficacy of any type 2 diabetes medication must be measured in terms of its ability to reduce the incidence of the condition’s complications, the organization noted that “at the time of FDA approval, canagliflozin had not been tested in a sufficient number of patients for a long enough period of time to answer that question.”
Urinary Tract Infections
Patients currently taking Invokana should remain vigilant for the symptoms of a urinary tract infection (UTI). As we now know, Invokana increases the risk of UTI, and reports have reached regulatory officials of these infections spreading into the blood or kidneys.
First, we’ll cover the symptoms of a basic UTI. Here’s what to look out for:
- pain or a burning sensation during urination
- more frequent urination
- an uncomfortable feeling that you have to urinate immediately, even though you may not produce any urine
- urine that is “cloudy” in appearance, or stained by blood
- pain in the lower abdomen
- low-level fevers and chills
When a urinary tract infection spreads to the kidneys, in a condition called pyelonephritis, symptoms become progressively severe and can hit extremely quickly. Fevers become higher and chills more violent, while nausea and vomiting frequently set on. Pain often becomes more pronounced, centralized in the lower back and usually confined to one side of the abdomen.
Scientists aren’t sure why, but cases of pyelonephritis can spread even further from the urethra, eventually infecting the blood. Symptoms of urosepsis, the severe condition that results, are similar to the ones we’ve already mentioned, but can also include an elevated heart rate and hyperventilation.
Both pyelonephritis and urosepsis are potentially deadly conditions. Some patients, in the absence of proper treatment, go into shock, as a rapid decline in blood pressure chokes the organs off from oxygen.
Invokana & Kidney Function
Kidneys, two bean-shaped organs in the abdomen, filter waste materials from the blood, producing urine which is eventually released from the body. In general, blood glucose, the body’s primary energy source, is caught in the kidney’s net and returned to the blood stream.
Invokana, along with other SGLT2 inhibitors, inhibits your kidney’s ability to “reabsorb” glucose. Rather than allowing sugars back into the bloodstream, Invokana makes kidneys release glucose along with other waste materials in urine.
The drug also seems to increase the level of creatinine, a waste product created by metabolizing muscles, in a patient’s blood. Creatinine is usually eliminated in urine, by way of the kidneys. In patients on Invokana, however, the kidneys are more likely to return the chemical to the blood stream. Increases in creatinine are usually associated with impaired kidney function.
What Are The Causes?
According to WebMD, kidney failure occurs when the kidney’s become unable to filter waste properly. When toxins are allowed to build up, the result can be death. Kidney failure can be both acute or chronic. Acute kidney failure occurs when the kidneys lose their ability to filter waste suddenly, over a matter of hours or days, while the chronic form occurs after a protracted period of kidney damage.
There are so many potential causes of kidney failure that a complete list would be impractical. Generally, though, these causes are broken down into three broad categories:
- Prerenal causes are ones that cut down on the supply of blood that reaches the kidneys, like dehydration or a physical obstruction in one of your veins.
- Renal causes, on the other hand, involve damage sustained directly by a kidney. Sepsis, a systemic infection that causes inflammation throughout the body, is one example. If the kidneys themselves become inflamed, they can stop working entirely.
Sometimes the kidneys become literally clogged. That’s what happens in a condition called “rhabdomyolysis,” which begins when muscles start to break down excessively somewhere in the body. Degrading rapidly, all these muscle fibers eventually enter the blood stream. But when they reach the kidneys, the organs are overwhelmed.
- Postrenal causes involve problems that impair the way urine exits the kidneys. After being filtered in the kidneys, urine travels through tubes called “ureters” and fills up the bladder.
Those tubes can get blocked up, by kidney stones or cancerous tumors, or they can become deformed after a traumatic accident. In either case, the kidneys don’t stop producing urine, but since the fluid’s path to the bladder is obstructed, pressure starts to increase in the kidneys. Enough pressure, and the organs can sustain damage, eventually shutting down completely.
Invokana, however, seems to take a very indirect route to kidney failure. In the FDA’s most recent announcement, the agency reported 19 cases of “life-threating blood infections […] and kidney infections […] that started as urinary tract infections.”
Aren’t Diabetics At An Increased Risk For UTI Already?
High amounts of glucose in the urine predispose many diabetics to urinary tract infections, according to physicians at Harvard Medical School. Currently, the agency has not proposed an explanation for why the infections are spreading from the urinary tract to the kidneys in Invokana patients. But if the drug increases the amount of blood glucose excreted in urine, it’s likely that it could also increase the risk for UTI.
Diabetics, both type 1 and type 2, already live at an increased risk for kidney damage, as well. In fact, diabetes directly contributes to around 44% of all cases of kidney failure, according to the National Institute of Diabetes and Digestive and Kidney Sciences.
Your kidneys are traced by millions of very thin blood vessels, and each of these vessels is itself studded by millions of tiny holes. This structure acts as a sieve or colander, literally filtering fluid of any larger molecules that can fit through the holes. But having high levels of blood sugar, like people with diabetes do, also raises the levels of other chemicals present in the kidney. Over time, these chemicals make the kidney’s filtering apparatus “leaky.”
Acute & Chronic Symptoms Of Kidney Failure
In some cases, kidney failure results in no symptoms. But more often than not, acute kidney failure causes:
- Abnormally low urine volume
- Swollen legs and / or feet
- Chest pain
- Fatigue or sleepiness
- Difficulty breathing
- Disorientation, confusion
In severe cases, kidney failure can also be accompanied by seizures, even coma. Chronic kidney failure, on the other hand, can present an array of “nonspecific” symptoms, side effects that are associated with numerous other medical conditions. As a result, many cases of chronic kidney failure are not diagnosed before permanent renal damage has occurred.
With that being said, the symptoms of chronic kidney failure generally develop slowly, over a long period of time:
- Hypertension, or high blood pressure
- Chest pain and difficulty catching one’s breath, both caused by possible fluid buildup in the lungs
- Swollen feet, ankles, and legs
- Chronic itchiness
- Impaired mental acuity
- Alterations in urine volume
- Decreased appetite
- Muscle twitching or tics
- Nausea and vomiting
Note those patients with both type 1 and type 2 diabetes are at an increased risk of developing chronic kidney disease, and of suffering acute kidney failure.
Acute kidney failure presents two severe complications:
- End-stage renal disease – a permanent loss of kidney function. Patients require either a kidney transplant or ongoing dialysis, in which the blood and body fluids are filtered by an external device, to survive.
- Death – impairment of kidney function is fatal if left untreated.
Chronic kidney disease results in a more varied list of potential complications. Since an increased amount of the body’s fluids are being retained, rather than expelled as urine, a patient’s blood pressure can become dangerously high. Pulmonary edema, in which the lungs fill with fluid, is also possible.
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Hyperkalemia, elevated levels of blood potassium, can alter the heart’s ability to function properly and permanent cardiovascular disorders may result. Pericarditis, in which the pericardium, a sac that surrounds the heart, is also fairly common in patients suffering from chronic kidney failure, as is anemia. The central nervous system can be damaged, leading to mood disorders, alterations in personality or seizures. The immune system can be compromised, making infections more likely. Over time, bones can become weakened, increasing the likelihood of a fracture.
Untreated, chronic kidney failure can lead to end-stage renal disease and become fatal.
Patients Consider Lawsuits
In light of kidney failure’s undeniable severity, QuarterWatch’s question becomes unavoidable: are Invokana’s potential benefits great enough to balance its possible risks?
Upon the drug’s approval, the FDA ordered Invokana’s manufacturer to conduct five additional safety studies. While the medical community waits for the results, patients who were prescribed Invokana and suffered kidney failure, kidney stones and other forms of renal impairment have begun to consider filing lawsuits. Amid allegations that Janssen Pharmaceutical, Invokana’s manufacturer and a subsidiary of global healthcare giant Johnson & Johnson, failed to warn patients of the drug’s risks, several patients have already filed complaints about severe cases of ketoacidosis. Prominent members of the legal community believe a wave of Invokana lawsuits is on the horizon.
Banville Law, a law firm committed to advocating for the rights of patients nationwide, has begun investigating potential Invokana claims. Our experienced team is offering free consultations to any patient who took an SGLT2 inhibitor and then experienced ketoacidosis or kidney damage. To learn more about your legal options, and receive a case eligibility evaluation at no cost, contact Banville Law today.