Farxiga

Farxiga

Dr K. here, your virtual pharmacist.  Today I will be venturing into new territory and discussing a diabetes medication that was approved on January 8, 2014 for use in the United States by the FDA.  On November 14th, 2012 the European Commission (the European Union’s equivalent to the US Food and Drug Administration or FDA) approved a new medication for type 2 diabetes for patients in the European Union (EU).  This medication, named Farxiga (Forxiga in Europe), is the first of its kind, known as an SGLT2 inhibitor.

It was created by a collaboration between two major drug companies that we are very familiar with here in the United States: Bristol-Myers Squibb and AstraZeneca.  This collaboration was also responsible for development of Onglyza, the diabetes medication that I discussed in my previous post.  The companies did present their studies to the FDA for approval in the US.  The FDA did not approve Farxiga at that time, because it was thought that the medication might cause certain cancers, which I will discuss a bit later.  Since 2012, the companies have done more studies and have gained FDA approval.

So the approval of Farxiga leaves us with many questions.  Is it safe?  How does it work?  What are the cancer risks, if any?  And, what are the basic things that you should know as you start taking this medication?  All of these will be addressed in today’s blog – I’ve done all of the research for you!

Farxiga – How It Lowers Blood Sugar 

Farxiga is a medication that works in your kidneys.  Your kidneys are responsible for controlling how much glucose leaves your body in your urine.  Farxiga works by making your kidneys “dump” more glucose into your urine so that it can leave your body, instead of holding onto the glucose and putting it back into your blood.  Remember, more glucose in the blood means higher blood sugars, and a not-so-happy diabetic.  The exciting thing about Farxiga is that it does not depend on insulin to work, so it can help diabetics at any stage and with or without the use of insulin (no shots needed!).

Farxiga and Your A1C

One study that I read found Farxiga caused patients to eliminate up to 70 grams of carbohydrates per day in their urine (about 280 calories).  Think about it, 70 grams of carbohydrates!  That’s more than the amount of sugar in one meal for a diabetic!  Farxiga can decrease fasting glucose levels by about 20 mg/dL and glucose levels 2 hours after you eat by 35-75 mg/dL.

And remember those carbohydrates can be thought of as calories too.  What happens when you decrease your calories?  You lose weight!  Over the course of the research trials (ranging from 24 to 52 weeks long) patients lost between 4 and 7 pounds on average – a big improvement over some of the other diabetes medications that cause weight gain.

Farxiga Dosages

For most patients, the normal dose of Farxiga is 10 mg, taken once daily at any time of the day.  Farxiga can be taken with or without food.  It should not be chewed, crushed, or split.  Patients with severe liver failure might be started on a lower dose of 5 mg.

Farxiga Side Effects

Side effects from the studies done on Farxiga so far seem to show that Farxiga is very well-tolerated in most patients.  Some of the more common side effects include low blood sugar when used with insulin or a sulfonylurea (glipizide, glyburide, glimepiride), genital and urinary tract infections, back pain, increased urination, and thirst.

The biggest concern with Farxiga is the potential for it to cause cancer.  When the makers of Farxiga were studying the side effects of the drug during their research, they put half of their patients on Farxiga and half of their patients on a placebo (“fake” pill with nothing in it).  After the patients had been on the medications for awhile, they evaluated the medical condition of people in both groups.  Neither group had a more significant amount of people with tumors.  But they did find that of the tumors that people in the Farxiga group had, there were more bladder, prostate, and breast tumors in this group than in the group on the placebo pill.

So what should we think?  Is Farxiga safe?  The patients on Farxiga that had tumors had not been taking Farxiga for very long before the tumors were diagnosed.  So does that mean that they weren’t caused by the medicine?  Possibly, but we can’t be sure.  Other studies did not find any difference in the amounts of tumors in patients when they tested the medication.  We have to remember too that the amount of patients with these tumors was higher in the group taking Farxiga, but it was not very much higher.  In “research terms” we call this “not statistically significant,” which pretty much is a fancy way of saying that it could be just a coincidence.  The FDA in the United States decided that there were too many questions left unanswered about these possible side effects, which is why it was not approved for use and is going through more research trials before it will come up for approval again.

Farxiga – Who Should Not Take 

If you have kidney disease, Farxiga is probably not the right medication for you.  Since Farxiga works by making your kidneys get rid of glucose, your kidneys have to be working well for this medication to do its best work.  Make sense? Farxiga has not been studied very much in patients with liver disease, but it is known that your body will not process the Farxiga very well if you have severe liver problems, so you should make sure your doctor is aware of your health condition before starting the medication.

When studying Farxiga before it was made available to diabetics, the manufacturers found that it can cause possible problems with the kidneys in certain patients, especially those over the age of 65 and those taking certain blood pressure medications.  If you are a patient at that age or on a blood pressure medication, discuss these with your doctor to find out if Farxiga is right for you.

Forxiga has not been studied in pregnant women, but did cause kidney problems in unborn rats.  Forxiga should not be used in pregnant women.  Also, women who are breastfeeding should not take Forxiga.

Forxiga Drug Interactions 

Farxiga may cause dehydration or low blood pressure when added to certain blood pressure medications known as “water pills” (examples: furosemide or hydrochlorothiazide).  If you are taking insulin or a sulfonylurea (glipizide, glyburide, glimepiride) you may be at greater risk of dangerous low blood sugars if you start taking Forxiga.  This list is not all-inclusive, so be sure your pharmacist and doctor know all of your current medications before starting Farxiga.

Farxiga Monitoring

As always, you will need to do daily blood sugar checks when on this medication.  Watch for the side effects I’ve listed above.  Your doctor will also be watching your A1c, as well as your kidney and liver functions when on this medication.

Farxiga and Diabetes Therapy

Since it is a new medication and does not have the “experience” of our more common medications for diabetes, most doctors probably won’t choose this first.  But it might be a good option for people that are on other medications and still have high blood sugars.

As a disclaimer, I am your “virtual” pharmacist, here to provide you with information and answers to questions.  However, I am not your local pharmacist and could, in no way, be aware of your specific medical needs.  Remember to always check with your medical provider and pharmacist before stopping or starting any new medications.  My posts are based on general pharmacy principles and should not considered as your “first opinion” when it comes to your health.  Please consult with your doctor and pharmacist about anything regarding your health.

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