A survey found 40 per cent of elderly people who live at home and are on medication take more than six kinds of medication, which might lead to deteriorating health.
About 30 per cent of them were also found to be taking drugs that might cause harmful side effects, according to the survey by the Tokyo Metropolitan Institute of Gerontology.
As elderly people often develop several chronic diseases, they tend to take various types of drugs. However, experts warn that too many drugs could lead to side effects because the body's ability to absorb medicine declines as people get older. Taking six or more kinds of drugs is said to increase the risk of deteriorating health, such as a tendency to fall down easily due to the interactions of the different drugs.
The survey results were presented at a conference of the Japan Geriatrics Society which started Friday and closed Sunday.
In the survey, nurses and others visited about 1,300 people 65 or older who were living at home in Tokyo in November and December 2013. Among them, 885 cases in which the details of medication had been confirmed were analysed.
The survey indicated that 36 per cent of them took six or more types of medication, and 9 per cent took 10 kinds or more. One of them took as many as 17 varieties of medication.
Using a simple test to check memory and other abilities, 11 per cent of those surveyed were diagnosed with cognitive function disorder. Among those who took six or more types of medication, the figure rose to as high as 18 per cent.
Twenty-eight per cent took one or more kinds of medicine that are not recommended for the elderly under US guidelines. Many of them took sleeping pills said to lower mobility functions that could make it easier for them to fall.
Elderly people "tend to take more and more medication because they visit several different medical institutions," said Hirotoshi Niikawa, a researcher of the institute who compiled the survey. "Drugs are necessary in some cases, but an increase of unnecessary medication could cause poor health. I want both doctors and patients to be careful."