Although the definition of polypharmacy is broad, encompassing the use of multiple medications, pharmacies and physicians, along with the potential for complex drug-drug and drug-condition interactions, one thing is for sure: It is a problem—especially for older adults.
The senior population (those aged 65 years and older) comprises 13.7% of the U.S. population but uses 40% of all prescription drugs. People aged 65 to 69 years fill an average of 14 prescriptions per year, and adults aged 80 to 84 years average 18 prescriptions per year, according to a 2009 report from the American Society of Consultant Pharmacists. Older adults also account for 30% of over-the-counter drug use, according to the National Council on Patient Information and Education.
A 2013 study the Journal of the American Geriatrics Society found that in a population of 1,000 adults aged 65 or older discharged from a hospital, at least one adverse drug event was identified in 18.7% of patients during the 45 days following discharge. Of those, 35% were seen as preventable.
Kyle Amelung, PharmD, senior clinical consultant for Express Scripts, says that prescribers need to balance the risk and benefit of multiple medications for one person. That means taking several factors into consideration, including assessing drug reactions and interactions when using two drugs, ensuring the right dose for the right person and incorporating nonmedical therapies to supplement drug treatment.
For example, taking warfarin and aspirin at the same time could cause gastrointestinal complications; or long-term use of an anti-clotting drug and aspirin could increase the risk of bleeding.
Polypharmacy could also cause a higher risk of falls, more hospital admissions, confusion, and an overall negative impact on morbidity and mortality, says David Brown, PharmD, founder and co-president, Middle Tennessee Pharmacy Services.
The problems of polypharmacy in older adults are exacerbated by:
2. Use of more than one prescribing physician and pharmacy;
3. Utilization of OTC medications, such as dietary supplements and herbal remedies that are often not reported to a physician;
4. Difficulty reading and understanding medication instructions;
5. Age-related, physiological changes;
6. Over- and under prescribing; and
7. Improper dosing.
The latter two are two of the most critical challenges for polypharmacy. A 2004 study in the Annals of Internal Medicine showed that the prevalence of omissions of appropriate medicines was 50%, while the prevalence of administering inappropriate medication was only 3%.
Regarding dosage problems, dosing might be appropriate at the onset of a condition and change as a patient’s status improves or worsens, or it might be based on inaccurate patient weight. Appropriate doses for warfarin, for example, could change more than once a week based on a patient’s target INR, a standard for evaluating blood coagulation.