 Many
of the same issues in kids apply to the elderly. Geriatric
patients, like children, may have relatively weak respiratory
muscles, making respiratory suppression a problem. But
as opposed to having less mature livers and kidneys, they
tend to have decreased hepatic and renal function due
to age and disease. Add to these factors the risk of falls
and fractures, and the concomitant use of many over-the-counter
preparations and the situation gets bleaker.
IT'S
NOT JUST OLD AGE
Recent research shows that many elderly patients remain
on the same drugs for many, many years, often without
changes in dose. But there's evidence of a fairly rapid
decline in drug metabolism as we age from 55 to 75.
So, a dose that might easily be tolerated in 55- or
60-year-olds may become increasingly toxic as they progress
through their seventh and eighth decades of life.
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Dangerous drugs for the elderly
Fallen and can't get up Falls
resulting in injury are a major concern for all
sedating drugs in the elderly, particularly those
who are frail, unsteady on their feet or infirm.
Benzodiazepines and opioids are the biggest culprits
here because they're more commonly used and have
long half-lives.
Toxic flip flop The problem
has grown with the advent of newer slow-release
opioids, such as the Contin series of drugs and
the fentanyl patch. A touted advantage of the
slow-release drugs is that there's less fluctuation
in serum drug levels, which minimizes the risk
of toxicity. The potential risk, however, is that
the longer half-lives can result in progressive
over-accumulation of drug in tissues, resulting
in increased toxicity.
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Drug toxicity may be misattributed
to the natural aging process itself. For example, increased
daytime somnolence and an unsteady gait are often chalkedup
to advanced age, when in fact these symptoms could be
drug-related.
ERR
ON THE SIDE OF CAUTION
Drug companies are reluctant to include the elderly
in trials because of the fear of lawsuits and adverse
events. Moreover, many geriatric patients also have
other concomitant illnesses that disqualify them for
clinical trials. As a result, physicians often have
little objective data to base their dosing decisions
on. Physicians must remember not to merely adjust for
weight when calculating drug dosages — even if
combined with hepatic and renal function tests. Further
physiologic differences between the middle-aged adult
and the elderly, especially those over age 65, should
always be considered.
Link to: "Kids
and clinical trials definitely don't mix"
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