The health of one in five adults in Tayside could be at risk amid a worrying rise in use of prescription drugs, researchers have warned.
A 15-year study of prescriptions found that 20.8% of adults in the region were being dispensed more than five drugs.
Dundee University, which carried out the study, said the findings raised “significant concerns” about adverse drug reactions.
It warned that prescription drugs could cause “considerable harm”, describing “potentially serious clashes between drugs prescribed for different conditions” as “common”.
Professor Bruce Guthrie, who led the study, said there were inherent dangers in “blindly following recommendations for drug prescriptions” when taking so many.
Around 6.5% of all emergency hospital admissions are now attributable to adverse drug events and the academic said at least half of those were “preventable”.
The elderly, people resident in a care home and people living in deprived areas were found to be most at risk as they are most likely to take 10 or more drugs.
The university looked at prescribing data for all 310,000 adults in Tayside between 1995 and 2010.
It found that the proportion of adults dispensed more than five drugs doubled, while the proportion dispensed more than 10 drugs tripled to 5.8%.
The results of the study and the “rising tide” of prescribed medications it has uncovered have been provided to the medical profession nationally.
“Prescribed drugs significantly improve a range of health outcomes, but they can also cause considerable harm,” said Professor Guthrie.
“Our study shows there has been a significant rise in the numbers of people receiving multiple drugs.
“This raises concerns because the simultaneous use of large numbers of drugs, what we call polypharmacy, can cause serious harm in some patients.
“More research is needed to better understand the impact on people’s health of multiple interacting drugs.”
In 1995, one in 17 adults was prescribed drugs with “potentially serious interactions” a figure that had more than doubled to one in eight adults by 2010.
The number of drugs prescribed was the characteristic most strongly associated with that increase.
Since older people were prescribed more drugs, 44% of those aged 70 years and over were prescribed drugs with potentially serious interactions in 2010.
Professor Guthrie said that as drug regimens become increasingly complex and potentially harmful, it was important that patients receive regular reviews and prescribing optimisation.