25% of people in the US aged 65 and over are now taking between 10 and 19 different prescription medicines each day, while 51% are taking at least five drugs daily, according to a new national survey.

Moreover, 57% of the seniors surveyed told the poll that they forget to take their medications, and the research showed that the more medicines they take, the more likely they are to fail to take them; 63% of those using five or more drugs say they forget doses compared to 51% among those taking fewer medications.

In addition, 34% of US seniors using five or more prescription drugs said that they did not feel knowledgeable enough about the drugs they have been prescribed or their potential side effects, while 35% were unsure they could name all the medications they use, according to the survey, which was conducted on behalf of pharmacy benefit manager (PBM) Medco.

Multiple medication use is also taking its toll on the financial health of America's older people, says the study; it found that the ability to afford their drugs is the greatest concern of 40% of seniors taking five or more prescription medications daily. Their next biggest worry relates to drug side effects (23%) and interactions (17%), while among those who are enrolled in the federal Medicare prescription drug plan (Part D), 37% said they are most concerned about not being able to afford their medications, with almost half (49%) saying they want to know how to delay or avoid falling into the so-called “doughnut hole.” This coverage gap occurs when an enrollee’s annual drugs bill reaches $2,700, after which they have to pay their costs out-of-pocket until their annual spending hits $6.,54. At that point, the federal government starts to pay again, covering 95% of the enrollee’s drug costs.

The survey also reveals that 60% of Medicare beneficiaries have taken some steps to delay reaching the doughnut hole, with 76% saying that they have switched to generic versions of their brand-name drugs and 39% reporting asking their doctors for free drug samples. However, only 27% told the survey that they use mail-order pharmacy to avoid the doughnut hole, despite the fact that, on average, seniors polled had also told the survey that using mail order had saved them around $540 a year, with 19% estimating that they saved at least $1,000 annually.