A Simvastatin is one of a clutch of cholesterol-lowering drugs called statins that came on the market about 20 years ago. These have now become among the most profitable drugs in history, and many drug companies have at least one statin in their armoury.

The reason statins are a drug salesman’s dream is that they are not prescribed for a defined illness, but for a condition which may or may not give rise to an illness. This means that it can be prescribed for virtually the whole lifetime of the putative ‘patient’.

The claim is that statins lower cholesterol levels in the blood, so reducing the risk of atherosclerosis (furred arteries) and, thus, preventing strokes and heart attacks.

Although studies have shown statins to be of value, for some people, the benefits have come at a high price. When the drugs were first marketed, their side-effects were claimed to be minimal, but experience over the years has shown them to be potentially very hazardous.

Simvastatin is one of the worst offenders in its drug class. A recent review found that it was the statin that caused the most rhabdomyolysis - severe muscle weakness that can release toxic muscle cell components into the circulation and so cause life-threatening conditions such as kidney failure (Ann Pharmacother, 2002; 36: 288-95).

Other serious problems now known to be caused by simvastatin include pneumonia, liver toxicity, pancreatitis, polyneuropathy (nerve damage) and fatal ulcerative colitis.

The manufacturer (Merck) says simvastatin’s main action is on the liver, where it reduces natural cholesterol output. However, independent researchers have found that the drug also crosses the blood-brain barrier, permitting it to have a direct action on the perfectly healthy (and necessary) cholesterol content of brain cells. This may explain the drug’s mental side-effects, such as depression, sleep problems and memory loss.

In the US, the authorities are so concerned about simvastatin that an independent task force has been set up by the National Institutes of Health to 'scrutinise' the drug and decide whether the risks of treatment may, in fact, outweigh the potential benefits.

The scientist in charge of the investigation, Dr Beatrice Golomb, has some interesting views on the current vogue for cholesterol-lowering drugs, which you may find relevant to your case. She is especially hostile to the idea of prescribing statins to older people because of the possibly fatal side-effects. 'For the older elderly, possible reductions in muscle function or thinking ability must be viewed as not only important to quality of life, but to survival,' she says.

Moreover, Dr Golomb questions the whole assumption that cholesterol is necessarily a bad thing. 'There are factors that might lead higher cholesterol to be of benefit selectively in the elderly,' she goes on to say. 'Among older elderly persons, for instance, those over age 75 or 80, higher cholesterol is actually associated with living longer, rather than with dying earlier.'