The statins are a group of drugs that are now the most frequently prescribed medicines in the world. Taken by millions of people, they generate mountains of profit for the drug companies.

Some of the names are atorvastatin, simvastatin, pravastatin, fluvastatin and rosuvastatin.

They all work by slowing down the amount of cholesterol your liver makes. Normally the average liver makes about 1,000mg of cholesterol a day.

Depending on the drug and the size of the dose, a statin can lower cholesterol by between 20 and 60%. Usually taken at night, it takes between four and six weeks to have maximum effect. The theory is that if you lower cholesterol, the risk of heart disease gets lower too.

But, thats not all the statins do. They also help relax blood vessels, reduce the stickiness of platelets and have antioxidant and anti-inflammatory activity. The combined actions therefore help in more ways than one to prevent heart attacks.

Like all drugs, however, they cause side effects. Some of them are minor, and some not so minor.

Statins can cause muscle pain and weakness, tingling in the legs, dizziness, depression, pancreatitis, heart failure and increase the risk of cancer.

One of the group was taken off the market because it caused many cases of rhabdomyolysis. This is where muscle fibres actually breakdown and release substances into the blood, causing kidney damage an extension of the muscle pain mentioned.

An unusual problem with statins is that they seem to interfere with co-enzyme Q-10. This enzyme makes energy for your body to function properly. If levels drop, less energy is available, especially to your heart muscle.

Statins affect both cholesterol production and CoQ-10 production, so may well make you feel tired and exhausted.

Normally, to keep your cholesterol down, you take a statin for life. Taking them for many years can throw up unexpected problems. One such is memory loss as minor forgetfulness or it can be a more problematical form, known as TGA or transient global amnesia.

TGA is where you lose chunks of your day, a few minutes or hours. You cannot recall what happened during that time. The drug manufacturers deny it, but many hundreds of people have reported TGAs.

Statins are not the wonder drug some people would have you believe.