Canada’s aging population is presenting a formidable challenge for the pharmaceutical industry and physicians. While the elderly are the largest consumers of drugs, there is still much to be learned about how aging bodies and medications interact.
“The elderly are a special population who respond differently to drugs than younger adults,” said Dr. Patrick Colin, Vice-President of Clinical Research at Axcan Pharma Inc. He presented at the 2nd Annual Meeting of Medication Use in the Geriatric Population, hosted by Baycrest Centre for Geriatric Care and the Ontario Pharmacists’ Association on September 19.
These differences can arise from altered pharmacodynamics and pharmacokinetics, as well as conditions that are common in the elderly, like reduced renal, hepatic or cardiac function. Concomitant illness, over-medication, or poor compliance are also potential factors. Between the ages of 40 and 80, the average adult loses about half of their kidney function.
“There is increasing pressure on the pharmaceutical industry to gather more data on the effects of drugs on the elderly,” said Dr. Colin, who gave the opening address to an audience of over 200 health-care professionals. “Elderly patients must be included in the clinical development of new drugs, new indications or new dosage drug formulations when the target population includes patients over 65.”
The 65-and-older demographic is expected to almost double in size by the year 2025.Dr. Colin warned that without more evidence-based data gathered from drug trials on this growing target group, there will be “increased prescription errors and adverse reactions in the future”.Dr. Colin reminded physicians in the audience that therapy adjustments are “essential” in the elderly. It’s not only important to prescribe the correct dose (start low and go slow is the best approach), but to regularly monitor the drug therapy in a patient in order to make the necessary adjustments. It’s also essential to obtain a complete drug history, consider interactions with other drugs, and look at non-drug alternatives if appropriate.
“If you don’t consider pharmacokinetics and pharmacodynamics of every drug that you prescribe to a patient, then you’re a risk taker,” said Dr. Walter Himmel, an emergency physician at North York General Hospital and Toronto East General. He presented on the topic of drug interactions in the elderly – an emergency physician’s perspective.
Many adverse drug interactions are predictable, said Dr. Himmel. He recommended that all prescribing physicians carry with them a pocketbook on drug interactions. Palm pilots are becoming an indispensable tool as well. He pointed to www.drug-interactions.com as an excellent site with “fantastic references and links”.