Thursday, 14 October 2010

MRCP revision battle 29.4: Lipid-lowering treatment

NICE recommends that all those with a 10 yr cardiovascular risk of >20% should be offered lipid-lowering therapy.

1st line: 40mg simvastatin
Measure LFTs when starting, at 3 months and at 12 months.

In primary prevention there is no 'target' cholesterol
In secondary prevention the target is less than 4mmol/l cholesterol and less than 2mmol/l LDL

If statins are not tolerated consider:
  • fibrates
  • ezetimibe
  • nicotinic acid

Mechanisms of action

Statins are HMG CoA reductase inhibitors.  They therefore work by decreasing the production of cholesterol in the liver.  The decreased production of cholesterol in the liver also results in the liver absorbing and processing more LDL, hence further reducing cholesterol.

Grapefruit juice decreases the metabolism of statins.  Patients on statins are therefore advised to avoid grapefruit juice as it would increase the risk of the rare side effect of rhabdomyolysis

Ezetimibe works by preventing intestinal absorption of cholesterol.

Fibrates are PPAR alpha receptor agonists.  They therefore increase clearance of VLDL and remnant particles and decrease TG secreation.

Fibrates and statins tend not to be used together due to increased risk of rhabdomyolysis.

Nicotinic acid (=vitamin B3) blocks breakdown of fats in adipose tissue. 
It can cause facial flushing.

For the really keen:
NICE lipid modification guide

After those heavy-going battles lets tackle something light - restless legs syndrome...