PRALUENT

Mar 1, 2017

By Trevor Shewfelt, Pharmacist at the Dauphin Clinic Pharmacy

The Gray Chopper? I guess it kinda looked like a spandex super hero costume. Anyway, that is what Brent, Pat's son, called Eric, my son while we went winter camping. The three adults were sitting around the tent drinking coffee. We are also procrastinating taking everything down and Eric got bored. I told Eric to go outside and play with the axe, or go walk across Singush Lake or something. These are not things he usually hears when we are sleeping in a house in Dauphin, so he happily ran out of the tent. I got to finish my coffee. When we got out of the tent, we saw 11 year old Eric dressed only in long johns splitting wood. Previous years on Louis Riel day, the mercury has dipped below minus 30. This year it was right around freezing and the Gray Chopper didn't feel the need to put on a coat or pants.

Just like winter camping, I've talked about cholesterol before. But this time, I've got a completely new type of cholesterol treatment to discuss. But, before you get too excited, the new treatments are probably too expensive for most people to take advantage of.

What is cholesterol? Cholesterol is a naturally occurring substance in the body that is essential for life. If you had no cholesterol in you, you would die. Cholesterol helps form bile acids in your digestive system, hormones in your endocrine system and important components of every cell membrane in your body. Although cholesterol is essential for life, you don't have to eat any. Your liver can make all the cholesterol you need.

So why does your doctor test your blood for cholesterol if it is essential for life? Why does your doctor care if your cholesterol is too high? Your doctor cares about blood cholesterol levels because if they are too high for too long you have higher chance of getting a heart attack or a stroke. Heart attacks and strokes account for about one third of all the deaths in Canada. That is more than any other disease.

When we talk about cholesterol, we throw around lots of letters. What does all this LDL, HDL, VLDL stuff mean? When your liver makes cholesterol, it puts it into the blood stream. Cholesterol is a kind of fat. Since blood is mostly water, cholesterol doesn't mix well with it. The liver has to mix the cholesterol with proteins to get it to stay in the blood. This mixture of cholesterol (which is a lipid or fat) and protein is called a lipoprotein. If you take a blood sample and spin it really fast in a centrofuge, it separates based on density. Different layers in the sample have different densities. Low Density Lipoprotein or LDL is often called "bad" cholesterol because it transports cholesterol from the liver to places like the lining inside the arteries. Through a complicated series of events, these cholesterol deposits can cause blockages that slow or stop blood flow. If blood flow to the heart muscle is stopped, that is a heart attack. If blood flow to the brain is stopped that is a stroke. High Density Lipoprotein or HDL is called "good" cholesterol because it transports cholesterol away from the cells lining the blood vessels. This can decrease the chance of blockages.

When we treat high cholesterol, the primary target of cholesterol lowering therapy is LDL. If LDL or bad cholesterol is high we have many, many studies saying high LDL increases the chances of the patient having a heart attack or stroke. The most common LDL lowering medications are called the statins. The statins stop the liver from making as much cholesterol. The statins do a good job of reducing LDL. We have lots of studies that show if we reduce someone's LDL with statins we can reduce the chances of heart attacks and strokes by 25% to 35% with five years' use

Now for some scientific tongue twisters. Praluent or alirocumab and Repatha or evolocumab are monoclonal antibodies. These are the names of the new cholesterol treatments. Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) is an enzyme that binds to LDL receptors in the liver. The LDL receptors in the liver help liver cells bind to, capture and remove LDL or bad cholesterol from the blood. When PCSK9 binds to a liver cell LDL receptor, it starts a process that destroys the liver cell LDL receptor. If the liver cell has less LDL receptors, it can remove less LDL or bad cholesterol from the blood. So more PCSK9 means less LDL receptors to remove LDL and the amount of LDL in the blood goes up. PCSK9 inhibitors like alirocumab and evolocumab bind to PCSK9 enzymes. Once bound to PCSK9, the new cholesterol treatments stop the PCSK9 from getting at the LDL receptors and destroying them. This means more LDL or bad cholesterol gets removed from the blood stream.

Let's talk cost and effectiveness of the new cholesterol treatments. Statins are what we use for cholesterol treatment most often now. Generic atorvastatin 80 mg costs about $30 per month or about $360 per year. Brand name Crestor 20mg costs about $80 per month or $960 per year. Praluent or alirocumab and rapatha or evolocumab cost about $650 per month or about $8000 per year. Statins are a pill you swallow everyday. Praluent is an injection you take twice a month. Rapatha can be a once or twice a month injection. The biggest problem with praluent and rapatha is they haven't been proven to reduce the number of heart attacks, strokes or deaths yet. Praluent and rapatha are probably best reserved for people who have genetically very high cholesterol.

Homozygous Familial hypercholesterolemia is very rare. About 1 in a million people have it. They have 2 copies of the high cholesterol gene. Their cholesterol is so high they can have heart attacks before they reach their teen years. Heterozygous Familial hypercholesterolemia is rare but more common. About 1 in 250 people have it. These people have only one copy of the high cholesterol gene. They have very high LDL cholesterol and a lot of history of heart disease in their family. These are the people for whom statin therapy often isn't enough to bring their LDL cholesterol down to normal. For these people the doctor might consider the new expensive injectable praluent or rapatha.

Icebergs the size of Prince Edward Island are breaking off of Antarctica. Droughts then floods are hitting California. These might be things people think of when they talk about global warming. I am now going to use our 2017 February winter camping trip as my example. Instead of trying to set up a tent in -27 C with a wind, I ditched the jacket and debated if I needed a toque. Mud was more of a problem than cold. And of course there was the 11 year old with his long johns and axe. All hail the Gray Chopper!

As always if you have any questions or concerns about these or other products, ask your pharmacist.

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.

We now have this and most other articles published in the Parkland Shopper on our Website. Please visit us at www.dcp.ca

Praluent official site - www.praluent.com

Familial Hypercholesterolemia Foundation - https://thefhfoundation.org/heterozygous-vs-homozygous-fh

Repatha official site - https://www.repatha.com/

Icebergs - http://www.cbc.ca/news/technology/iceberg-breaking-antarctica-larsen-1.3924091

 


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