The statistic revealed for the first time in a study published on Monday suggests Australias elderly are taking more drugs, more often, than their counterparts in the US and UK.
Experts arent sure why. Nor are they sure why the trend appears to be increasing.
But they are worried. Although many people take multiple medications for good reason, taking five or more medicines together is linked to an increase in a persons risk of frailty, disability and death.
You talk to patients, they've been started on a medicine 20 years ago, and they are still on it. And quite often they dont know what they are taking the medicine for, says Dr Danijela Gnjidic, a University of Sydney researcher who has published several papers on the issue.
In some cases those medicines can interfere with each other. The symptoms of this are often mistaken for a new illness leading to a person being given more drugs. It is a dangerous cycle, says Dr Gnjidic.
Researchers have long suspected "polypharmacy", as it is known, is a major issue in Australia, but until this study had not had firm statistics on the size of the problem.
Dr Amy Page and her colleagues analysed dispensing data for medicines given to people aged over 70 between 2006 and 2017 on the Pharmaceutical Benefits Scheme, looking for people who were on more than five medications at a time.
They arrived at an estimate of 935,240 people 36 per cent of people in that age bracket. More than 153,000 of them took more than 10 different medicines, with about 17,000 taking over 15.
That number has increased in the past decade, both as a total number and as a proportion, despite efforts to tackle it.
Part of the increase is because we have more people living into old age which is a wonderful thing, says Dr Page, a researcher at The Alfred hospital and lead author of the study published in the Medical Journal of Australia.
But we have also shown the prevalence is increasing as well. And thats not such a wonderful thing.
The study did not assess whether the medications were appropriate for the individual, Dr Page cautioned.
And there is no direct evidence taking multiple medications causes harm, only that it is linked to an increase in risk.
But there are concerns. Medicines can interact in complex and unpredictable ways. Taking many pills is expensive. Having to juggle a complicated pill regime raises the risks of making a mistake taking too many of the wrong pill, for example.
And many medications are approved as safe based on clinical trials on young, healthy people. It is not clear if they are more or less safe for the elderly, Dr Page said.
Dr Gnjidics 70-year-old father just hit the polypharmacy cut-off, his fifth daily medication. So I have been having long conversations with him and with his GP, she says.
She encourages anyone taking multiple medications to talk to their pharmacist and GP to ensure they are still appropriate.