A New Class of Drugs - Invokana

Is Invokana Right for You?

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Invokana (canagliflozin) belongs to a new class of drugs known as sodium glucose co-transporter 2 (SGLT2) inhibitors and is the first of the SGLT-2 inhibitors to be approved by the FDA as of the spring of 2013. Invokana, an adjunct to diet, and exercise can help to lower blood glucose. SGLT-2 Inhibitors work with the kidney by sending glucose (sugar) out of the body through the urine. Sugar is reabsorbed by the kidney and, instead of re-entering the blood stream it, is excreted via the urine.


What Does the SLGT-2 Protein Do and Why Should We Inhibit It?
SGLT-2 is the protein that helps to reabsorb sugar in the kidney. In fact, ninety percent of reabsorption occurs through SGLT-2. The SGLT-2 protein is similar to a tunnel, and when the tunnel opens, glucose that has been filtered through the kidney can travel back to the blood stream. Normally, we want to reabsorb glucose so that other important nutrients in the kidney are not filtered into the blood stream. However, people with diabetes have too much SGLT-2 and the body is unable to spill some of the glucose into the urine, therefore all the sugar is sent back into the bloodstream contributing to elevated blood sugars.   

Researchers have sought to inhibit the SGLT-2 protein so that excess sugar can spill into the urine and not into the blood stream. The inhibitor in Invokana is called, canagliflozin. Canagliflozin turns off SGLT-2 proteins mechanism of action and causes excretion of glucose in the urine.


How Can This Medicine Help Me?
As with any medication, you must weigh the positives and negatives before taking Invokana. Studies have shown that Invokana can help to lower HgbA1c by 0.7-1%. In addition, by excreting glucose into the urine, your body isn’t using that sugar as fuel, so weight loss is possible.

Invokana may also help to reduce blood pressure, and some studies also suggest that Invokana can help to increase good cholesterol. But as there's still not a great deal of long-term safety and efficacy data for the drug, Invokana isn't a first-line treatment option at this point.

What are the Side Effects?

According to The Food and Drug Administration, the major side effects of Invokana include dehydration, vaginal yeast infections, low blood pressure, and penis yeast infections. You should not take Invokana if you are allergic to any of its ingredients (read package insert), if you have severe kidney problems, or are on dialysis. The dosage of Invokana can be adjusted depending on your kidney function. Your doctor should do a blood test to assess your kidney function before prescribing this medication. You’ll also want to tell your doctor if you are following a low-sodium diet, are pregnant or plan to become pregnant, or are breastfeeding. Lastly, inform your doctor or Certified Diabetes Educator of all your medicines, supplements, and herbal remedies. Invokana can affect how well your medicines work and vice versa.

Alert your doctor if you take any of the following: 
•     diuretics (water pills) 
•     rifampin (used to treat or prevent tuberculosis) 
•     phenytoin or phenobarbital (used to control seizures) 
•     ritonavir (Norvir®, Kaletra®, Lopinavir ®)* (used to treat HIV infection) 
•     digoxin (Lanoxin®)* (used to treat heart problems)  

How Will I Take the Medicine? 
Currently, a lack of long-term data inhibits the use of Invokana as the first line of treatment when it comes to choosing diabetes medicines. Instead, if your physician decides that Invokana is the right medicine for you, it will likely be added as a second agent. For example, if you are using Metformin and your blood sugars are not at goal, your physician may add on Invokana. 

Invokana is prescribed as 100mg or a 300mg dose. The medication should be taken before the first meal of the day. Ask your physician which dose is appropriate for you. 

Can I Afford Invokana?
Typically, newly approved medications are expensive.

But, the good news is that some people may be eligible for programs that can aid in reducing the cost. If you have private health insurance, you may be eligible for The Invokana CarePath Savings card provided by Janssen Pharmaceuticals (the manufacturer of the medication). This card can save you about a year’s worth of medication cost, a $1,200 maximum benefit. For more information about this saving go to: www.invokanacarepathe.com or call 877-468-6526. Other ways to save cost on this medication is to look into patient assistance programs offered by Johnson and Johnson 800-652-6227 or research your state pharmaceutical assistance programs (SPAPs). These types of programs are state specific but can help residents pay for their drugs. For more information about your status visit: www.mymedicarmatters.org

Other Important Things You Should Know: 
•    Invokana works best when taken in conjunction with a healthy diet and exercise plan. 
•    Because Invokana causes extra sugar to be excreted in the urine, you will test positive for sugar on a urine test. 
•    Excess sugar in the urine can cause yeast infections and urinary tract infections. 
•    Invokana can cause elevated potassium levels in the blood. 
•    If you are taking Invokana with another hypoglycemic agent such as insulin or a sulfonylurea your chances for low blood sugar are increased. 
•    You may feel the urge to urinate more or have a larger urine output when taking Invokana. 
•    Invokana is not meant for people who have ketoacidosis. 
•    Call your doctor is you are experiencing any side effects that are bothering you and do not go away. 

Other Medicines of This Class:

  • Dapagliflozin (Farxiga®)
  • Empagliflozin (Jardiance®)

For more information about oral diabetes medicines: All About Oral Diabetes Medicines


http://www.rxlist.com/invokana-drug/indications-dosage.htm Accessed December 20, 2013

http://www.fda.gov/downloads/drugs/drugsafety/ucm346637.pdf Accessed December 20, 2013

Gebel, Erika, Ph.D. New SGLT-2 Meds Target the Kidneys. Diabetes Forecast. http://www.diabetesforecast.org/2013/jun/new-sglt-2-meds-target-the-kidneys.html Accessed 20 December 2013

Gustaitis, Joseph. Affording Invokana. Diabetes Self Management. 2013; 33. 

Schernthaner, Guntram, et al. Canagliflozin Compared With Sitagliptin for Patients With Type 2 Diabetes Who Do Not Have Adequate Glycemic Control With Metform Plus Sulfonylurea: A 52-week randomized trial. Diabetes Care. http://care.diabetesjournals.org/content/early/2013/03/28/dc12-2491.abstract Accessed online December 22, 2013

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