ProLipid

Prominent drugs containing statins include Lipitor® and Zocor®, the world's best selling and fifth best selling drugs in 2005, respectively.

Statins lower blood cholesterol levels by blocking a process in the liver responsible for producing cholesterol. This is done by inactivating an enzyme called HMG-CoA reductase, which is why statins are also known as HMG-CoA-reductase inhibitors.

How Statins Work

1. Without Statins

Without statins, the enzyme "HMG-CoA reductase" produces lots of cholesterol (yellow dots) in the liver. Cholesterol is then transported to the blood, causing high levels of LDL cholesterol.

2. With Statins

Taking a statin drug blocks HMG-CoA reductase; the extent depends on the type and dose of the statin. Because less cholesterol is produced, less LDL cholesterol circulates in the blood. This reduces the buildup of atherosclerotic plaque and the risk of coronary heart disease.

When Statins inhibit the production of cholesterol, the liver's need for cholesterol can no longer be met by self-synthesis. Thus, the liver starts absorbing cholesterol from the blood, resulting in a drop of the serum levels of LDL cholesterol. Statins can lower LDL cholesterol by 30 to 50% when taken in standard doses. For a comparison of the LDL-lowering capacity of different statins, please have a look here.

Statins are a relatively new class of cholesterol lowering drugs; the first statin was approved by the FDA 20 years ago, in 1987. They are considered to be relatively safe. Muscle problems and gastrointestinal symptoms such as flatulence, congestion or nausea are some of the more common side effects, although they are not frequent. A rare (normally less than 1 in 10,000 patients) but serious side effect is rhabdomyolysis which causes parts of the muscles (the rhabdomers) to disintegrate. When this muscle debris begins to damage the kidneys, kidney failure may result.

The drug Baycol® (elsewhere named Lipobay®) containing cerivastatin had to be withdrawn from the market in 2001, because rhabdomyolysis occured approximately 10 times more often than with other statins. Care must be taken if statins are combined with other cholesterol lowering drugs such as nicotinic acid and fibrates. The danger of rhabdomyolysis increases if statins and fibrates or nicotinic acid are taken together.