Invokana - A New Diabetes Medication
Jul 8, 2014
By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy
Ever had a bad smell in your house? Have you ever not been able to identify the source? Our pantry had one of those. But everything in the pantry looked good. It was mostly full of dry goods and cans. There were some onions in the corner, but they were okay too. I couldnt find the source of the smell. My wife Doris couldnt find the source of the smell. So, Doris started interrogating the children. Emily will make a master criminal. She didnt crack under the hot light and denied all knowledge. Eric was a different story. His confession began with actions from quite a while ago.
Just like Eric, our diabetes story starts a while ago. Back in February, Lori Berard gave a wonderful talk at the Annual Diabetes Expo at the Seniors Center. One of the things she mentioned is there was a new drug coming that would let you pee out extra sugar. That new drug is here! It is called Invokana or canagliflozin.
Before we get to how Invokana or canagliflozin works, lets do a diabetes review. Diabetes is when your body has trouble using sugar. There are 3 main types of diabetes: type 1, type 2, and gestational diabetes. Type 1 diabetes is when your pancreas doesnt produce insulin. You must inject insulin or you will die. Type 1 diabetes accounts for about 10% of diabetics. In Type 2 diabetes, your body may produce normal, or even above normal amounts of insulin. However, other parts of the body like your muscle and fat cells arent listening to the insulin signal. Type 2 diabetes can be treated with diet, exercise, pills or insulin. Type 2 diabetes accounts for about 90% of diabetics. Gestational diabetes is a temporary condition that occurs during pregnancy. It affects approximately 2 to 4 per cent of all pregnancies. Gestational diabetes increases the risk of developing diabetes later in life for both mother and child.
In Type 1 diabetes, the body cant produce any insulin. Insulin acts like a key to open doors in the cells to let sugar in. Without insulin keys, there is no way to open the doors in the cells. The sugar stays in the blood stream. That means the blood sugar level stays high, but the cells have no energy to use. Type 2 diabetes is a little different. The pancreas produces insulin. It may even produce higher than normal amounts of insulin. The problem seems to be with the little locks on the sugar doors in the cells. The little locks seem to have gotten rusty. Even if insulin keys go into the locks, the keys cant turn and the doors wont open. We call this insulin resistance, and we think this is the main problem in Type 2 diabetes.
In Type 1 diabetes we must inject insulin. In Type 2 diabetes, it is not as straight forward. We can inject insulin. With enough insulin keys, we can force those rusty lock open. We can give pills that force the pancreas to produce more insulin. They have names like glyburide. They work well, but eventually the pancreas will get tired and stop producing insulin. Or we can give medications like metformin which act like WD-40. This makes the locks easier to turn. Acarbose blocks an enzyme in your digestive system that breaks carbohydrates down into glucose. That way the glucose isnt absorbed and the carbohydrate stays in the gut. Recently, we got new tools called incretins like sitagliptin that block an enzyme that breaks down GLP-1 in the gut. More GLP-1 in the gut delays the emptying of the stomach, makes the pancreas produce more insulin, reduces glucagon secretion and convinces your brain that you are less hungry.
Invokana is a new class of drug for Type 2 diabetes called an SGLT2 inhibitor. It inhibits a sodium-glucose co-transporter in the kidneys. This means the kidney wont reabsorb as much glucose out of the urine, and you will essentially be peeing out excess sugar.
When used by itself, invokana or canagliflozin has a low chance of making the blood sugar go too low. It has some unusual effects as well. Canagliflozin may make the blood pressure go down a little and may make a persons weight go down a little. On the downside, canagliflozin will make urinary tract infections and yeast infections happen more often because of all the sugar in the urine. Because canagliflozin makes you urinate more, the patient will be at increased risk of dehydration. This can be a problem in older people. The dehydration can affect potassium levels especially in people taking blood pressure pills like ACE inhibitors, ARBs or potassium sparing diurectics. Canagliflozin may also increase LDL or bad cholesterol.
Eric finally cracked under interrogation from Doris. On the last day of school he left his half eaten lunch in his lunch kit. Then he put the whole lunch kit away in the pantry. I dont think it was malicious so much as forgetful. But the sealed containers in the lunch kit started fermenting. The discovery we made is that it takes about 3 weeks for them to pop and start oozing noxious gases. Who says kids dont learn anything during summer break?
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The information in this article is intended as a helpful guide only. It is not intended to be used as a substitute for professional advice. If you have any questions about your medications and what is right for you see your doctor, pharmacist or other health care professional.