Why Older People Respond Differently to Medication
Many people are surprised to learn that the same medication can affect individuals in very different ways. A medicine that works well for one person may not work well for someone else or may even cause unwanted side effects. Often, this isn’t due to age, weight or lifestyle alone; it can come down to small differences in our genes that affect how our bodies handle medicines.
At Whiddon, we believe that understanding these natural differences is an important part of safe, person‑centred, relationship‑based care. By learning how genetics can influence medication response (a science known as pharmacogenomics), we can better tailor treatments; reduce trial and error; and support the comfort, wellbeing and dignity of every person in our care.
How the Body Processes Medication
When we take medication, our body works to absorb it, use it where it is needed, break it down and eventually clear it from our system. This process doesn’t work the same way for everyone. Some people’s bodies absorb or break down medicines quickly, while others do it more slowly. Some people are more sensitive to some medications, while others are less sensitive.
Take, for example, a person whose body breaks down medications slowly. Some medicines may stay in the body for a longer period than expected. Because of this, a standard dose might feel much stronger than it once did, or it may lead to side effects like drowsiness or an increased risk of falls.
Every individual’s body works at its own speed, which is why a “one size fits all” approach to prescribing is rarely the best fit for older people.
Complex Health Needs and Conditions
Many older people have complex health needs or multiple conditions, such as dementia, heart conditions, and bone and joint issues. Supporting these complex needs often involves taking several medications, each prescribed with the intention of improving comfort, function, or quality of life. When multiple conditions and medications are involved, the body can respond to medicines in less predictable ways. This means that certain medications may have a more pronounced impact on a person’s balance, mood or cognitive clarity.
How DNA and Ageing Intersect
While age is a major factor, our genetic makeup also plays a critical role in how we feel after taking a treatment. Research shows that humans share approximately 98% of their genetic code, yet it is the remaining 2% codes for proteins that determines our unique response to medications.
Within these small genetic differences are instructions that tell the body how to make proteins that move medications around, break them down, and guide every step of how medicines work in the body. Some individuals are genetically predisposed to be “slow metabolisers”, meaning they absorb medicines at a slower rate. When a naturally slower metabolism caused by ageing is combined with these genetic factors, the risk of a medication-related problem can increase.
Supporting Safe and Individualised Care
With medication-related issues amongst older Australians contributing to an estimated 250,000 hospital admissions in Australia each year1, finding a more precise way to manage care is a priority.
Through our Australian-first trial, Whiddon is identifying early signals through pharmacogenomic testing. This information is designed to support decision-making, providing doctors with additional insights to tailor care to the individual’s unique biology. While this work remains subject to peer-reviewed publication, our focus remains on the person behind the diagnosis. By understanding the link between multiple conditions and unique genetics, we are helping to ensure that every resident, especially those with the most complex needs, can live with the greatest possible dignity and ease.
For more information on our clinical trial and its progress, visit the PGx page.
References
- Lim R, Ellett LMK, Semple S, Roughead EE. The Extent of Medication-Related Hospital Admissions in Australia: A Review from 1988 to 2021. Drug Saf. 2022;45(3):249-57.
