MRC/BHF Heart Protection Study

Facts about Statins

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Facts about Statins

  • Statins are a group of drugs that reduce LDL cholesterol in the blood.
  • Statins reduce LDL cholesterol (or "bad" cholesterol) by inhibiting an enzyme called HMG-CoA reductase. This enzyme normally regulates cholesterol synthesis in the liver; and when the enzyme is inhibited, the production of LDL receptors on the surface of the cells is increased, and these extra receptors remove more cholesterol from the blood stream. Statins typically reduce LDL cholesterol by about 25-40%; they also reduce triglycerides (human fats), while raising HDL cholesterol (or "good" cholesterol) by a small amount. Hence, the total cholesterol level is reduced.
  • Several statins are available, including atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Mevacor), pravastatin (Lipostat), simvastatin (Zocor) and, until it was withdrawn recently, cerivastatin (Lipobay). All have similar effects on cholesterol, but have different biological properties and potencies.
  • Statins can be taken in one daily dose (rather than several times a day) which helps with compliance. Doctors usually recommend taking the dose in the evening because it is slightly more effective
  • Simvastatin (Zocor), the statin used in the MRC/BHF Heart Protection Study (HPS), was the second statin discovered and has been used since 1988. It has been taken by more than 35 million patients in 117 countries and is one of the world's most widely used cholesterol drugs.
  • Statins are effective at lowering cholesterol for people of all ages, are well tolerated and have very few side-effects. Most people who take statins do not notice any effects at all. There are two uncommon side-effects which doctors need to be aware of when prescribing statins. One is an effect on liver enzymes which is usually unnoticed by the patient, but may need monitoring and sometimes withdrawal of the drug. Before starting on statins, the doctor tests the patient's blood to assess liver function and then repeats the test at intervals while the drug is being taken. The second is that statins can occasionally affect the muscles, causing muscle pain or weakness, and leakage of the muscle enzyme creatine kinase into the blood stream. This muscle problem is reversible if the tablets are stopped, but can rarely lead to widespread muscle breakdown (known as rhabdomyolysis) with kidney problems, and very rarely this has caused death. An unacceptable number of cases of muscle problems led to the withdrawal of cerivastatin (Lipobay), but it has only very rarely been a problem with the other approved statin regimens.
  • The Scandinavian Simvastatin Survival Study was the first clinical trial to demonstrate conclusively that long-term therapy with statins substantially reduced the risk of death from all causes, as well as from cardiac events, in middle-aged patients with coronary heart disease and raised cholesterol. Subsequent trials have shown similar results; these included two large trials of pravastatin in patients who had already suffered a coronary event (LIPID and CARE), one trial of pravastatin as a primary prevention treatment (WOSCOPS), and one of lovastatin as a primary prevention treatment (AFCAPS). Such results established the efficacy (i.e. reduction in coronary disease events) of cholesterol-lowering in some circumstances, and the tolerability of long-term daily statin therapy, but doubts have remained about how widely statins should be prescribed. The HPS will help address this question and provide substantially more safety information.