Statins Flashcards
Examples of statins
Rivaroxaban & simvastatin
How do statins work?
Statins reduce serum cholesterol levels. They inhibit 3-hydroxy-3-methyl-glutaryl coenzyme A (HMG CoA) reductase, an enzyme involved in making cholesterol. They decrease cholesterol production by the liver and increase clearance of LDL-cholesterol from the blood, reducing LDL-cholesterol levels. They also indirectly reduce triglycerides and slightly increase HDL-cholesterol levels. Through these effects they slow the atherosclerotic process and may even reverse it.
Indications for statins
Primary prevention of cardiovascular disease: to prevent cardiovascular events in people over 40 years of age with a 10-year cardiovascular risk >20%.
Secondary prevention of cardiovascular disease: first line alongside lifestyle changes, to prevent further cardiovascular events in those who already have evidence of cardiovascular disease.
Primary hyperlipidaemia: first line, in conditions such as primary hypercholesterolaemia, mixed dyslipidaemia and familial hypercholesterolaemia.
Contraindications of statins
Statins should be used with caution in patients with existing hepatic impairment. They are excreted by the kidneys, so the dose should be reduced in people with renal impairment. You should avoid prescribing statins to women who are pregnant (cholesterol is essential for normal fetal development) or breastfeeding.
Side effects of statins
Generally safe and well tolerated.
Common: headache and gastrointestinal disturbances. Serious: effects on muscle. These can range from simple aches to more serious myopathy or, rarely, rhabdomyolysis. They can also cause a rise in liver enzymes (e.g. alanine transaminase [ALT]); drug-induced hepatitis is a rare but serious adverse effect.
Interactions of statins
The metabolism of statins is reduced by cytochrome P450 inhibitors, such as amiodarone, diltiazem, itraconazole, macrolides and protease inhibitors. This leads to accumulation of the statin in the body, which may put patients at increased risk of adverse effects. Amlodipine has a similar interaction although the mechanism is less clear. To reduce this risk you may need to reduce the dose of the statin or, if the other drug is being used for a short period only (e.g. a course of clarithromycin therapy), withhold the statin.
Elimination of statins
Hepatic
Patient information on statins
Statins are taken orally on a once daily, traditionally taken in the evening, as there is some evidence that they have a greater effect when dietary intake is at its lowest.
Explain you are prescribing a medicine to lower cholesterol levels to reduce the risk of a heart attack or stroke in the future.
Advise patients of common side effects, and to seek medical attention if they experience muscle symptoms (e.g. pain or weakness).
Ask your patient to come back for blood tests in 3 and 12 months.
Advise them to keep alcohol intake to a minimum.
Those taking simvastatin or atorvastatin should avoid grapefruit juice, which inhibits the cytochrome P450 enzymes that metabolise statins and may therefore increase the risk of side effects. This is not the case for pravastatin and rosuvastatin.
