Most of us believe that, as we get older, we’re going to suffer increasing disability and illness, and medicine convinces us that it’s just a natural part of aging. To deal with the symptoms of decline, we’re given a variety of prescription drugs - usually in combination. It’s now commonplace for the over-65s to be taking five or more medications on a regular basis.
Yet, far from being a fountain of youth, prescription drugs - especially in combination - may well be hastening the problems of old age: physical frailty, loss of vital-organ function and even mental decline.
The tendency of doctors to dole out multiple drugs to the elderly is worrying because this population group is getting larger by the day. Today, 13 per cent of the US population is over 65, a figure set to rise dramatically in the coming years. Yet, seniors consume, on average, 30 per cent of all prescription drugs (Health Prom Dis Prev, 1992; 8: 127-41). In the UK, the over-65s account for 18 per cent of the population, but nearly half of all prescription drug use (Pharm J, 1997; 259: 686-8).
And these figures are conservative as drug use among the elderly is believed to be grossly underreported.
Doling out drugs
The problem lies in the way doctors approach healthcare in the elderly, and their sketchy knowledge of which drugs are both effective and appropriate for this age group. A recent large-scale study of more than 765,000 seniors showed that more than one-fifth of their prescriptions were inappropriate for their age group (Arch Intern Med, 2004; 164: 1621-5). Ten years ago, a widely publicised report revealed that nearly a quarter of elderly Americans were being prescribed one or more medications that were countraindicated for this patient population (JAMA, 1994, 272: 292-317).
But the most dangerous practice of all - practised all over the world - is polypharmacy, where several different drugs are prescribed at once without sufficient understanding of how these drugs react in combination.
Most older Americans, for example, take an average of three to five drugs (J Am Geriatr Soc, 2001; 49: 277-83), and that doesn’t include over-the-counter medications or herbals. In Canada, 91 per cent of older patients are taking one or more drugs (prescribed or over the counter) - the average per patient was more than four apiece (Ann Emerg Med, 2001; 38: 666-71). In the UK, at least a third of patients over 75 are taking four or more prescription drugs (BMJ, 2004; 329: 434). An Australian survey of more than 200,000 veterans found that:
* more than half were taking more than five separate drugs
* one-fifth were taking more than 10 drugs
* around one in 14 was taking more than 15 drugs
* one in 30 was taking 20 drugs (Aust NZ J Public Health, 1997; 21: 469-76).
While this kind of reckless prescribing used to be confined to nursing homes, it’s now a risk faced by anyone over the age of 50. Besides ignoring the inherent dangers of interactions between drugs, doctors increasingly prescribe drugs ‘off label’ - that is, for conditions and at dosages different from those approved, a well-known major cause of adverse drug reactions.
As the number of drugs taken increases, the risk of adverse effects increases exponentially. Compared with taking only one drug, the risk of ill effects when taking five increases by a further 4 per cent. But if 16 drugs are taken, the added risk skyrockets to 54 per cent (Clin Geriatr Med, 1990; 6: 293-307).