Hyperlipidaemia

Question 1

Why is hyperlipidaemia a problem?

Answer 1

It is a major risk factor for atheroscelrosis and therefore IHD.

Question 2

What is the mechanism of action of statins?

Answer 2

HMG CoA reductase inhibitors. This is the enzyme involved in the 1st committed step in cholesterol synthesis.

This leads to a reduced plasma cholesterol.
The reduction in hepatic cholesterol synthesis leads to an upregulation of hepatic LDL receptors, promoting LDL uptake.

Net effect: less cholesterol and less LDLs (35% reduction)

So higher HDL:LDL ratio

Question 3

Describe the impact statins have on mortality?

Answer 3

Reduced 5 year mortality by 30%.

Reduced 5 year mortality from IHD by 42%.

Question 4

Who should be started on statins?

Answer 4

Anybody post MI.
Anyone with a 10% 10 year CVD risk.
Anyone with high cholesterol.

Question 5

List the other antihyperlipidaemic medications and their basic mechanisms of action?

Answer 5

Choleystyramine (bile acid binding resins) Binds bile acids reducing absorption of fat.

Fibrates: e.g bezafibrate, gemofibrozil 2nd line class after statins.
Alters lipoprotein metabolism increasing metabolism of VLDL's and TG's.

Choleterol absorption inhibitors: Ezetimibe