Statins
Statins are a group of drugs that reduce blood cholesterol levels by inhibiting an enzyme called HMG CoA reductase, a rate-limiting enzyme in the cholesterol biosynthetic pathway. This means that statins slow down the production of cholesterol and increase the liver's ability to get rid of LDL cholesterol in the blood.
Statins are used for the prevention of heart attacks and strokes, in persons with coronary heart disease (CHD), Peripheral arterial disease, history of stroke and anginas. Statins are also used for, the prevention of possible coronary or cardiovascular events, because of factors such as hypertension, smoking and diabetes mellitus.
Statins reduce cholesterol levels, but they also prevent atherosclerosis by improving endothelial function, modulating inflammatory responses in blood vessels, maintaining vascular plaque stability and preventing thrombus (clot) formation. The effects of statin therapy, however, are more pronounced after sustained lipid lowering for one and a half to two years.
Lovastatin was the first statin to be approved by the FDA to treat hyperlipidemia in 1987. Since then, seven more statins have been introduced, the most effective of which seems to be Rosuvastatin. Several studies and controlled clinical trials have been conducted to test the efficiency of statins and it was found that they can reduce LDL by up to 50%. With sustained reductions of total and LDL cholesterol levels over time, the risk of cardiovascular disease mortality and events declines significantly. Several clinical studies showed that for each LDL cholesterol reduction of 1.0 mmol/L, the risk of cardiovascular events was reduced by significantly and steadily reaching up to 36% reduction after 5 years of treatment.
Cholesterol production levels increase while sleeping, therefore, statins are prescribed to be taken at night. Statins are generally safe; they are generally well tolerated and major side effects are rare. Side effects include myopathy and rhabdomyolysis - skeletal muscle damage (a very rare but significant side-effect), headaches, altered liver function tests (rarely, hepatitis), paraesthesia (altered sensation), and gastrointestinal effects including abdominal pain, flatulence, diarrhea, nausea and vomiting. Rash and hypersensitivity reactions (including angioedema and anaphylaxis) have been reported, but are very rare.
Statins interact with a number of other medications. The concomitant use of statins with fibrates (e.g. gemfibrozil) or nicotinic acid (niacin) in lipid regulating doses or with immunosuppressants such as ciclosporin is not recommended because this may increase the risk of muscle toxicity. The concomitant use of statins with other lipid lowering drugs (fibrates other than gemfibrozil, ezetimibe or nicotinic acid in lipid-lowering doses) should be undertaken with caution, and generally under specialist supervision. Moreover, concomitant use of 'azole' antifungal agents and HIV protease inhibitors may increase plasma levels of statins and thus increase the risk of side effects such as muscle damage.
Grapefruit juice consumption can significantly alter or interfere with statin metabolism, thus increasing the risk of serious myopathy. These concerns do not apply to fluvastatin or to pravastatin and rosuvastatin, which are metabolized by a different enzyme.
Statins in summary: Statins play an important role in the prevention of cardiovascular disease by reducing cholesterol levels in the blood. Treatment should be sustained and under the supervision of a specialist to monitor progress and avoid possible interactions with other drugs. Statins are generally safe and side effects are rare.
