On a busy morning when the surgery waiting room looks like Heathrow's departure lounge during an air traffic control strike, it can be hard to believe that half of the people who have crammed into the building, apparently desperate for their doctor's advice, will never take the medicines they have been given.
But that is what the statistics show. According to a 2002 report by the Cochrane Collaboration (the experts in reviewing evidence-based medicine), about half of all medicines are not taken as prescribed. And what's more, it's not because patients are forgetful. It's because they're not convinced the treatment which their doctor has prescribed is the right one. This mistrust costs the NHS £230m a year in unused pills - which is one reason this week has been declared Ask About Medicines Week.
This chronic mistrust is no surprise. It's something I see every day in surgery. Take antidepressants, for example. I may see a person crippled with severe depression who desperately wants help. You might think I was home and dry: that accepting a prescription that the evidence says will help was a no brainer. But you'd be wrong.
Either the patient has heard a scare story about antidepressants or they have a relative who took some for a similar condition and was never the same again. If I could arrange counselling for them it wouldn't be so bad, but on the NHS that is a rare commodity, so they leave untreated and often return far worse.
Beta blockers - such as atenolol - are another example. They have come in for a lot of stick in the press recently following the publication in the medical journal Lancet in September of a report which showed they were no longer an effective first-line treatment for blood pressure. As a result, many patients have just stopped taking the drug, despite the fact that their blood pressure has been adequately controlled by it for years, unaware that sudden withdrawal can lead to some pretty serious side effects including angina.
And then there are tranquillisers such as valium, the mere mention of which generates a negative response because so many people were hooked on them in the past. And while that's a good reason to be cautious, these drugs can really help in the treatment of conditions such as acute anxiety, back muscle spasm and whiplash.
Perhaps this shouldn't be surprising. The days of people being unquestioningly deferent to anyone in authority are long gone. And, thanks to the media, people are much savvier about health matters. Every newspaper has a health page and you can go online and Google a drug such as Prozac and discover more than five million opportunities to find out more about it. But does that mean that patients now think they know better than their doctors? Or do they simply not trust us any more?
Research conducted by the Medicines Partnership - a group of doctors, patients and representatives from the drugs industry - suggests that the issue is thankfully not about trust but about lack of information. And that in all demographic groups, most patients want to take a more active role in decisions about their treatment. They don't want their doctor to assume a paternal role, prescribing treatments for which there is good evidence for effectiveness and safety. Patients want more: they want to know far more about potential risks and side effects than we are letting on.
Who can blame them? All medicines are potentially dangerous chemicals, all of which come with a seemingly endless list of potential adverse reactions. Why should patients let them pass their lips without knowing in detail what they may be letting themselves in for?
Doctors need to accept that they need to start sharing the decision-making process. Otherwise all these unused prescriptions will continue to result in unnecessary and preventable ill health - and a massive bill for the taxpayer.
Reader's problem
A reader asks: I heard on Radio 4 that Vitamin D supplements are a good idea for young children. Is this true?
Simon says: Children who lack Vitamin D are at risk of developing rickets, which leads to weakness and deformity of developing bones. The most risky period for this is between six months and three years, when children go through a major growth spurt. Happily, the disease is rare in developed countries where most children get enough Vitamin D from their diet - it's found in oily fish, egg yolk and dairy products - and from natural sunlight - which the body converts into the vitamin. So as long as a child is getting enough sunlight and has a good diet, they are unlikely to benefit from supplementation.
· To ask Simon a question email health@theguardian.com. He cannot enter into correspondence.
