Polypharmacy, part 1. Pitfalls of multiple medications: taking multiple drugs and risk of interactions.

The Bottom Line

  • Many older Canadians are taking multiple medications (polypharmacy) to manage their health conditions.
  • When combined, some medications (or food and herbal supplements) can interact with each other, producing unexpected side effects.
  • Polypharmacy (taking 5 or more medications) can increase your risk for interactions.

A growing number of older adults are dealing with more than one medical condition at the same time. Examples include diabetes, hypertension, heart disease, or arthritis (1-3). To manage these conditions, people are often prescribed multiple medications to be taken each day (2;3). They may be taking several different drugs and also vitamins, herbs, and other food supplements. Taking multiple medications and supplements has the potential to lead to several problems. Being on several (poly) medications (pharmacy) is termed “polypharmacy”.

A number of different aspects of polypharmacy in the aging population have been studied by researchers. We have prepared a four part series describing some of the most important issues related to polypharmacy . In each of the four parts we will show you how aging and taking multiple medications can sometimes bring about unexpected problems. Part 1 discusses what we mean by the term polypharmacy and why it is important.

Why is polypharmacy important to your health?

Although there are different definitions of polypharmacy, the most common definition is the use of five or more medications taken in the previous two days (3;4). Some of the reasons that polypharmacy is a daily routine for older adults include:
a) having more than one medical condition, 
b) easy access to insurance that covers medications, 
c) easy access to family physicians or other medication prescribers,  
d) easy access to more and more research that recommends using medication (3), and
e) using  medication(s) to treat the unrecognized adverse effects caused by another medication  

What does the research show us about polypharmacy?

Reliable Canadian sources inform us that polypharmacy is a very common issue in older adults. In 2009 the Canadian Institute for Health Information reported that 63% of older adults took five or more prescription medications every day, and 23% took ten or more medications (5). 

What are some important things to know about polypharmacy?

Medications may cause interactions with each other in many ways.  When combined, some medications increase the overall effect on your body. For example, both aspirin and warfarin can significantly increase the risk of bleeding, so when they are used together, the combined effects increase the risk of bleeding.  In contrast, certain medications, when combined, decrease the overall effect of each medication; for example taking antacids at the same time as an antibiotic reduces the body's ability to absorb the antibiotic, which reduces its effect.  When some medications are combined, they may produce a new effect that can be helpful but sometimes harmful. 

What is the bottom line about polypharmacy?

Many older Canadians are taking multiple medications when they are managing several health conditions. Medications (including vitamins, herbs, and other food supplements) can be very helpful but can also be harmful if there are interactions. 

This four-part series of blog posts explores various aspects of polypharmacy. In Part 2, we will discuss how aging changes the way our body responds to medications, including when taking multiple medications. Part 3 looks at online drug interaction checkers. Part 4 examines medication reviews.

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  1. Canadian Institute for Health Information. Canadian Institute for Health Information (CIHI). Seniors using five or more types of prescription drugs. 2010. http://www.cihi.ca/CIHI-ext-portal/internet/en/document/types+of+care/pharmaceutical/release_18mar2010.
  2. Canadian Institute for Health Information (CIHI. Canadian Institute for Health Information (CIHI). Seniors and the healthcare system: what is the impact of multiple chronic conditions. Toronto, Canada: CIHI; 2011. 
  3. Patterson SM, Hughes C, Kerse N, Cardwell CR, Bradley MC. Interventions to improve the appropriate use of polypharmacy for older people. Cochrane Database Syst Rev 2012;5:CD008165.
  4. Ramage-Morin PL. Medication use among senior Canadians. Health Rep 2009 Mar;20(1):37-44.
  5. Canadian Institute of Health Information. Canadian Institute for Health Information (CIHI). The baby boom effect: caring for Canada's aging population. 2011. http://www.cihi.ca/CIHI-ext-portal/internet/EN/document/health+system+performance/quality+of+care+and+outcomes/release_01dec11.

DISCLAIMER: These summaries are provided for informational purposes only. They are not a substitute for advice from your own health care professional. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the McMaster Optimal Aging Portal (info@mcmasteroptimalaging.org).

Many of our Blog Posts were written before the COVID-19 pandemic and thus do not necessarily reflect the latest public health recommendations. While the content of new and old blogs identify activities that support optimal aging, it is important to defer to the most current public health recommendations. Some of the activities suggested within these blogs may need to be modified or avoided altogether to comply with changing public health recommendations. To view the latest updates from the Public Health Agency of Canada, please visit their website.