Statins, also known as HMG-CoA reductase inhibitors, are drugs that are prescribed for people with high levels of cholesterol. They block the action of an enzyme (HMG-CoA reductase) made in the liver that is required to produce cholesterol, hence their name, HMG-CoA reductase inhibitors.

The human body needs cholesterol in order to function. However, high levels can lead to atherosclerosis - when cholesterol-containing plaques accumulate in the arteries and undermine blood flow. Statins reduce blood cholesterol levels, and in doing so reduce the risk of developing stroke, heart attack and angina.

Statins have been linked to various adverse events (undesirable side effects), and many lay people wonder whether they are good or bad. The aim of this article is to show some studies which looked at the harms and benefits of statins.

Diabetes risk - scientists from St. George's University, London, England, and the University of Glasgow, Scotland examined five statin trials that had been published from 2005 to 2010. They found there was a link between high statin doses and diabetes risk - patients on high doses of statins had a 12% higher risk of developing diabetes. However, they emphasized that the benefits - reducing serious heart problems - far outweigh any risks. (Link to article)

Low heart-risk patients - researchers from the Cochrane Heart Group at the London School of Hygiene and Tropical Medicine in London, UK, stated that there is not enough evidence that statins benefit low-risk heart disease patients. Team leader, Fiona Taylor said doctors should be cautious about prescribing them to low-risk patients, especially in light of evidence on how statins affect people with no history of cardiovascular disease. (Link to article)

Hemorrhage history - a study carried out at Massachusetts General Hospital and Harvard Medical School, Boston suggested that patients with a history of hemorrhage may find that statins increase their risk of recurrence to the point that this outweighs any benefits (Link to article). They wrote:

"A particular subgroup of patients for whom the advisability of statin use is unclear are those at high risk for intracerebral hemorrhage (or a stroke caused by bleeding within the brain). The reason for added concern is the increased incidence of intracerebral hemorrhage observed among subjects randomized to statin therapy in a clinical trial of secondary stroke prevention."

Childhood lupus - children with lupus should not be given statins, even though their condition raises the risk of developing coronary artery disease later on in life, researchers from Duke University Medical Center revealed in a study. They said that even though statins have a positive effect on lipid levels and CRP (C-reactive protein), their effect on atherosclerosis is not considerable enough to warrant their routine use for children with lupus. They said the rare long-term risks associated with statins outweigh the benefits. (Link to article)

Statins and liver damage

Liver damage - statins can cause levels of liver enzymes to increase. If this is slight, most patients can continue taking the medication. However, if the increase is severe, the patient will have to stop, otherwise there is a risk of eventual permanent liver damage.

Patients on some medications, such as gemfibrozil (Lopid) and niacin have a higher risk of developing liver problems if they are also on statins.

Patients on statins should have a blood test six weeks after starting on them in order to check liver function. Then, there should be annual blood tests if no liver problems were detected.

Statins and muscle problems

Statins may cause statin myopathy - there is inflammation of the muscles. The patient feels muscle pain and tenderness. The higher the statin dose, the more likely a patient will experience these pains.

In severe cases rhabdomyolysis can develop - the muscles break down and release the protein myoglobin into the bloodstream. Myoglobin can damage the kidneys.

Patients on certain medications have a higher risk of rhabdomyolysis. These include niacin, cyclosporine, nefazodone, gemfibrozil, antifungal medications, and erythromycin (Erythrocin).

Any patient on statins who starts having muscle pains should tell their doctor.

According to the American Heart Association:

"For the person who experiences myopathy with a statin, other alternatives should be discussed with their physician. Patients who are taking statins and not experiencing any side effects should continue to take their medication unless advised for other reasons to stop by their healthcare provider. Only the very rare side effect of rhabdomyolysis (muscle injury), signaled by dark urine, should lead a patient to stop their statin immediately but then talk promptly with their healthcare provider." (Link to statement)

Effect of statins on brain cells

A 2009 study published in the Journal of Lipid Research reported that statins can have profoundly varying effects on brain cells, both good and bad effects. The authors said that doctors should take great care when determining what dosage patients should be prescribed, especially the elderly.

John Albers and team compared simvastatin and pravastatin on neurons and astrocytes (two types of brain cells). Astrocytes support cells that help repair damage. They applied the drugs directly to cells thus eliminating the drugs' differences in crossing the blood-brain barrier. They found differences in both types of cells and between the drugs. Simvastatin reduced the astrocytes' expression of cholesterol transporter ABCA1 by about 80%, while pravastatin did the same by 50%. Both statins increased expression of the Tau protein in astrocytes and neurons - Tau protein is linked to Alzheimer's disease. Pravastatin also increased the expression of amyloid precursor protein (APP), another Alzheimer's hallmark.

Brain cholesterol levels tend to be reduced during old age. The researchers wondered whether among elderly individuals, the effects of stain therapy might have the potential to transient or permanent cognitive impairment. (Link to article)

Scientists in The Netherlands, however, found that statins can protect nerve cells against damage known to occur in the brains of patients with Alzheimer's disease. We know that nerve cells eventually die as a result of overstimulation, a process known as excitotoxicity. The Dutch scientists overstimulated nerve cells in animal experiments and found that when treated with a statin (Lovastatin) the death of those overstimulated nerve cells could be prevented. The statins also prevented loss of memory capacity that typically occurs after the death of such cells. Statins stimulate the protective capacity of tumor necrosis factor, which is closely involved in the brain's immune response.

In animal experiments they demonstrated that this tumor necrosis factor has a very beneficial effect on nerve cells and can protect them against death. (Link to article)

Statins and tendon complications

In 2008, researchers at Rouen University Hospital in Rouen Cedex, France identified 96 cases of tendon complications between 1990 and 2005 which were attributed to statins. Conditions included tendon rupture and tendonitis (majority of cases).

Their study showed that of 4,597 side-effects linked to statins, approximately 2% were attributed to tendon complications, with symptoms generally occurring within 8 months of starting statin therapy. The Achilles heel was the most common tendon affected, with swelling, warmth, stiffness and pain as the most common symptoms. Seventeen of the patients had such severe symptoms that they had to be hospitalized. The symptoms started after the patients began taking statins, and improved after statins were stopped, and then came back when therapy was restarted.

A considerable number of tendon complications may go unreported, they added. Although the prevalence of tendon complications with statins is low, all statins have the potential to cause such problems, even at recommended dosages. (Link to article)

Are statins good or bad

The answer to that question cannot be a simple one. If a person has a severe liver reaction when on statins, then they are obviously bad. However, a good doctor will find that out. Most studies agree that the benefits of statins, if prescribed properly and to suitable patients, far outweigh the risks.

Written by Christian Nordqvist

Original article date: 30 April 2004
Article re-written: 08 September 2011