Polypharmacy: The Real Landscape of Clinical Prescribing

Sheldon H. Preskorn, MD

Dr. Preskorn is Professor, Chair, Psychiatry and Behavioral Sciences, University of Kansas School of Medicine, CEO, Clinical Research Institute

Today’s prescriber has more therapeutic options, each with different pharmacodynamics and pharmacokinetics, to understand and weigh than ever before.

In addition, treatment over the last several decades has moved from a focus on time-limited therapy of an acute illness to preventive or maintenance therapy for chronic illnesses as diverse as major depressive disorder (MDD), schizophrenia, Alzheimer’s disease, hypertension, human immunodeficiency virus infection, and atherosclerosis. For this reason, patients are much more likely to be on more than one medication at the same time. In fact, they are likely to accumulate preventive therapy as they age.

As would be expected given the above, age is repeatedly found to be a risk factor for polypharmacy. However, some may be surprised to learn that being on a psychiatric medication is a greater risk factor for polypharmacy than is advanced age. Further, the percentage of the different populations on a unique combination increases in direct relationship to the average number of drugs used to treat that specific population. Finally, one study found that the percentage of the population on ≥ 8 medications doubled as a function of the number of different prescribers the patient saw.

There are numerous reasons why psychiatric medications mark a population at risk for polypharmacy. First, psychiatric illnesses have an increased frequency in patients with other medical problems. Second, patients with one psychiatric illness are at increased risk for other psychiatric disorders. Third, patients with depressive and anxiety disorders are high utilizers of healthcare services and thus may be treated symptomatically with other medications. Regardless of the reason, the prescriber should be aware of this fact and take it into account when developing the treatment plan for their patient.

The use of multiple psychiatric medications has increased over the last 2 decades, probably reflecting both the increased availability of effective medications and the fact that they have a more focused or limited pharmacology. The latter leads to better tolerability but may also limit efficacy and, thus, require the use of more medications to optimize patient outcomes.

These factors may explain at least in part why the use of multiple psychiatric medications to treat patients is on the rise. Patients on psychiatric medications are at risk for DDIs, and these DDIs are likely to involve more than just two drugs.