Benefits outweigh risks for majority of patients

Like all drugs, statins are not without some side effects, including muscle pain and sexual dysfunction, writes MUIRIS HOUSTON

STATINS ARE USED in patients with high cholesterol and for the prevention of heart attacks and strokes. They decrease the manufacture of cholesterol by blocking the action of an enzyme called HMG-CoA reductase.

The benefits of statins are well established and unquestionable, and, reassuringly, they outweigh the risk of side effects in the majority of patients. However, like all drugs they are not without some side effects.

Probably the most well-known side effect from statin drugs is muscle pain (myalgia). It occurs in between 1.5 and 3 per cent of people who take the cholesterol-lowering medication.

In rare cases, this can progress to a condition called rhabdomyolysis, where muscle fibres actually break down, releasing a substance called myoglobulin. In large concentrations it may cause kidney damage. Statins are also known to increase liver enzymes, which may mean having to stop the drug.

In recent years, the product characteristics for many drugs in the statin class have been updated to include some additional side effects. Patients should be made aware that treatment with any statin may sometimes be associated with depression, sleep disturbance, memory loss and sexual dysfunction. The exact cause of these side effects is unclear.

Statins inhibit the enzyme HMG-CoA reductase before the final formation of cholesterol, and this same pathway is used to synthesise coenzyme Q10. The result can be a deficit in the amount of coenzyme Q10 needed for optimal heart and skeletal muscle function. This could lead to impaired enzyme activity in mitochondria – the cells’ powerhouses.

However, while low blood concentrations of coenzyme Q10 have been noted in patients taking statins, concentrations in muscle have not consistently shown this pattern.

A number of small studies suggest coenzyme Q10 may have a role in treating statin-induced muscle pain. There is also some evidence that using the supplement may help strengthen muscle performance in heart failure.

However, a 2007 review in the Journal of the American College of Cardiology noted there was little evidence that muscle coenzyme Q10 levels were reduced in patients with myopathy.

“The conclusion of this review is that there is a general lack of consistency with respect to the efficacy of coenzyme Q10 in clinical trials, and the consensus is that coenzyme Q10 should not be routinely recommended.

“However, the supplement appears to be relatively safe and could be tried in patients who cannot tolerate other methods of treating their myopathic symptoms, such as a change in dose or change in drug regimen,” it said.

For patients at high risk of a cardiovascular event and those who have already had a heart attack, taking statins and making lifestyle changes means they have a significantly reduced risk of a further heart attack or stroke.

As well as lowering levels of bad cholesterol, statins are believed to have two additional helpful modes of action within the cardiovascular system: the drugs are believed to stabilise plaques, the collections of fat that block diseased vessels – thereby preventing clots breaking off from the plaques – and also appear to have an anti-inflammatory effect on blood-vessel walls.