Lecture 7 - Hyperlipidaemia Flashcards
What is the function of cholesterol?
Maintains membrane integrity (fluid when cold, more rigid when hot)
Precursor in production of steroid hormones
Bile acid precursor
Vitamin D precursor
What is the clinical risk of having a high level of cholesterol?
Leads to high level of LDL which has the longest half-life
LDL susceptible to oxidation at damaged endothelium, ROS contributes to endothelial dysfunction increasing adherence of lipid rich deposits and foam cells formed (macrophages engulf oxidised LDL) leading to formation of atheromatous plaques
What is HDL?
Carrier of cholesterol that takes cholesterol away from circulation not tissues that need it and the liver for disposal in bile
How does levels of total serum cholesterol affect the risk of coronary heart disease?
Inc total serum cholesterol = Inc risk of coronary heart disease
How can you non pharmacologically modify cholesterol levels?
Exercise
Diet modification
How does a reduction in total cholesterol by 10% affect 10 year Coronary Heart disease mortality?
15% reduction in 10year CHD mortality and 11% total mortality
What are some familial forms of hypercholesterolaemia?
LDL receptor gene mutation (reduced reuptaake of LDL from circulation)
Apolipoprotein B gene mutation
How to statins work to reduce blood cholesterol?
Competitively inhibits the action of HMG-CoA REDUCTASE preventing the conversion of HMG-CoA to melanovate which is needed to produce cholesterol
Also increases clearance of LDL
Besides reducing circulating LDL (transporter for cholesterol) what are the other benefits of statin therapy?
Improved vascular endothelial function (inc NO, Vascular Endothelal factor decreased)
Stabilisation of atherosclerotic plaques by decreasing smooth muscle proliferation and inc collagen
Improved haemostasis - decreased fibrinogen, platelet aggregation and. Inc fibrinolysis
Anti inflammatory - dec proliferation of inflammatory cells
Antioxidant - reduced Super Oxide formation
What are some statins?
Atorvastatin
Simvastatin
Rosuvastatin
Why is simvastatin typically taken at night?
It has a relatively short half life compared to atorvastatin
Cholesterol is made in its highest quantities at night so best time for simvastatin to have the largest effect is night
What are the adverse effects of statins?
Muscle pain
GI disruption
Nausea
Headache
Rare - RHABDOMYOLYSIS
Inc liver enzymes
When are statins contraindicated?
Renal or hepatic impairment
PREGNANCY or Breast feeding
What are the important drug-drug interactions for statins?
CYP3A4 important since amiodarone, diltiazem, and macrolides increase plasma conc of Statin
Amlodipine increases plasma conc of statin
How would drinking grapefruit juice affect levels of statins and other drugs?
Why?
Levels of statin increase
Grapefruit Juice inhibits CYP3A4 which is the metaboliser for statins so statins are broken down more slowly so their levels increase
What is a primary prevention for Cardiovasular disease?
Interventions for individuals at high risk of cardiovascular disease
What is a secondary prevention for cardiovascular disease?
Intervetniosn for individuals who already have cardiovascular disease