A number of new US studies have pointed up the need for extra care in medicating older people, with government figures showing that older people with disabilities are more at risk for taking “inappropriate” medicines.

33 of medicines are regarded by physicians as inappropriate for people aged 65 and over, but around 25% of US seniors with disabilities use at least one prescription drug which is inappropriate for people of their age, as do 13% of over-65s without disabilities, according to the Agency for Healthcare Research and Quality (AHRQ).

These drugs - which include such widely-used products as the anxiety treatment Xanax (alprazolam) and antianginal Procardia (nifedipine), both made by Pfizer, and the pain relievers Darvon (propoxyphene) and Demerol (meperidine) – should not be used by older people because they are ineffective, pose a high risk of side effects or could be replaced by safer alternatives, says the Agency.

Meantime, researchers have reported a study showing that older seniors taking drugs for both dementia and incontinence had a 50% faster decline in function than those taking dementia drugs only.

The study, by Dr Kaycee Sink of Wake Forest University School of Medicine in North Carolina, looked at residents of nursing homes, where the two most common medical conditions, dementia and urinary incontinence, are often present in the same patient. Of the residents studied, about 10% of those being being treated with cholesterinase inhibitors for dementia were also taking either Pfizer’s Detrol (tolterodine) or Ortho-McNeil’s Ditropan (oxybutynin), both anticholinergics and the two most commonly prescribed treatments for urinary incontinence.

It is likely that the oppositional effects of the drugs contributed to the accelerated decline in these patients, said Dr Sink, who described the findings, published on-line by the Journal of the American Geriatrics Society, as representing a major public health problem.

The results of another study by Dr Sink, presented earlier this month at the American Geriatrics Society Meeting in Washington, showed that patients being treated with anticholinergic drugs walk more slowly, have worse memory functions and are less able to take care of themselves than people of the same age who are not on the drugs.

Widely-prescribed products which have mild or moderate anticholinergic properties include GlaxoSmithKline’s ulcer treatment Zantac (ranitidine) and Pfizer’s Procardia. Moreover, drugs which are not generally through of as anticholinergics, such as Sanofi-Aventis’ edema treatment Lasix (furosemide) and Abbott Laboratories’ blood pressure and angina treatment Cardizem (dialtiazem) can also, when taken together, hasten functional and cognitive declines by an average of three to four years, the study found.

- In April, case findings presented to the American Academy of Neurology by Dr Jack Tsao of the US Uniformed Services University of the Health Sciences (USU) showed that, among a group of people with an average age of 75, the cognitive function in those who took anticholinergic drugs declined 1.5 times as fast as in those who did not.