The most frequently wasted medication classes were antibiotics, benzodiazepines, and antihypertensives Table 1. Many of the medications listed as frequently wasted are taken episodically rather than in a stable daily pattern. Table 1 also shows that the most frequently wasted medications (eg, antibiotics) are not necessarily the most prescribed or the costliest.
Table 1 also shows the total annual relative costs of wasted medication by pharmaceutical class. Benzodiazepines, antidepressants, and antihypertensive medications combined accounted for a third of the total annual costs due to waste. The reasons for waste of medications and the relative contribution of each to total waste are presented in Table 2. The perception by subjects that a medical condition had resolved or that a medication was ineffective accounted for more than half of the cost due to waste. Physician and geriatric nurse practitioner perspectives are not captured by these data.
Discussion
On the basis of comprehensive home assessments, our study provides an estimate of wasted medication and the reasons for it in an outpatient population of older adults.
Most waste derived from 2 factors: the resolution of the condition for which the medication was prescribed and perceived ineffectiveness of a medication for its purpose. Together these 2 reasons accounted for more than half of the costs. This finding implies that acute conditions are central to waste, especially when medications for such conditions have high unit costs. Further support for the importance of acute conditions was that higher yearly drug expenditures were associated with lower percentage waste. Thus, high annual drug costs reflected stable, efficient patterns of medication use.
Although it may be difficult for clinicians to estimate how many pills to dispense, efforts should be made to determine the effectiveness and tolerability of medications before prescribing full quantities. Judicious use of samples is a possible remedy for this problem. Small prescriptions requiring multiple pharmacy visits would not help, but research on optimal prescribing quantities might lend some insight. Physicians should encourage patients to finish prescribed antibiotics if tolerated and not needlessly change prescriptions when previous pills remain. Further suggestions for promoting medication compliance in older adults are available in the medical literature.9
Limitations
We emphasize that our pilot study was small and not necessarily generalizable, yet it has made progress in a neglected area of research. As employees of the retirement community, the physicians caring for these patients are motivated to be fiscally responsible, and for this reason the mean annual waste detected in our study may, if anything, have been a substantial underestimate. Also, some subjects may have been overly optimistic in concluding that they intended to use all of a prescription medication on an as-needed basis. The lack of drug co-payments in this population, however, may predispose to more waste.
Based on our interviews, we found it uncharacteristic of most subjects to throw any pills away, but further underestimation could have occurred because of forgotten disposal of medicines. Researchers were motivated to find waste but could find none for 48% of subjects. Those subjects seemed sure that waste was absent.
Even though we counted more than 2000 wasted pills, numbers of specific medications were small. Thus, our analysis was confined to broad pharmaceutical classes and overall reasons for waste. This limitation could be overcome in more focused studies of specific wasted medications.
Conclusions
If, as we found in our study, average medication waste of $30 per person-year represents a conservative estimate, given that there are nearly 35 million individuals older than 65 years in the United States,10 the total national costs due to medication waste would not be less than $1 billion per year. Clearly, further studies in varied populations are required to confirm our waste estimate, and more research is needed to find effective waste reduction strategies. Despite the limitations of our study, physicians should begin to take note of what happens to prescribed medicines. That may serve as the most immediate basis for waste reduction.
Related resources
The Drugs and Devices Information Line Contains links to pharmacoepidemiology resources, maintained by the Pharmacoepidemiology Program, Harvard School of Public Health. http://www.hsph.harvard.edu/Organizations/DDIL/ddilhpge.html
Topics of Pharmacoepidemiology and Pharmacoeconomics A listserv for discussions related to these areas. http://www.findmail.com/list/pharmacoepidemiology/
ISPE—International Society for Pharmacoepidemiology A non-profit international professional organization dedicated to promoting pharmacoepidemiology. http://www.pharmacoepi.org/index.htm
Pharmacoepidemiology and Drug Safety The official journal of the International Society for Pharmacoepidemiology http://www.interscience.wiley.com/jpages/1053-8569/
Acknowledgment
The author acknowledges the assistance of the following undergraduate research assistants: Allison Robbins, Barbara Jones, Eva Liu, Karen Walp, Cynthia Oberto, Amanda Cook, John Raser, Sarah Hamilton, Anjali Godambe, and Michelle Anatone. Allen Dietrich, MD, provided guidance in the planning and execution of the study. Harlan Krumholz, MD, and Jerome Kassirer, MD, of the Yale University Robert Wood Johnson Clinical Scholars Program provided critical review of the manuscript.