Identifying and Communicating Clinically Meaningful Drug–Drug Interactions

Abstract

Objective:

Providing care to patients with comorbid medical problems may result in complicated, multiple drug therapy regimens, increasing the risk of clinically meaningful drug–drug interactions (DDIs). The purpose of this article is to describe the prevalence of DDIs and provide examples on how to identify and intervene on DDIs.

Methods:

We described DDI data from the Utah Drug Regimen Review Center, where adult Medicaid patients were reviewed by pharmacists from 2005 to 2009. Patients were selected by the number of prescriptions filled per month (>7) or having a high RxRisk score.

Summary:

A total of 8860 patients were reviewed, and 16.6% had at least 1 clinically meaningful DDI. Patients with DDIs were slightly younger (mean age 45.2 vs 48.2), more likely to be female (75.0% vs 68.9%), and had more prescriptions per month (13.4 vs 12.5) compared to patients without (P < .001). Pharmacodynamic DDIs were more prevalent (80.2%) than pharmacokinetic. Pharmacodynamic DDIs mainly occurred with drugs used to treat psychiatric/seizure/sleep disorders (69.4%) and pain/migraine (56.6%). Pharmacokinetic DDIs mainly occurred with drugs used to treat psychiatric/seizure/sleep disorders (53.2%), cardiovascular diseases (46.3%), and infectious diseases (29.6%).

Conclusions:

Clinically meaningful DDIs are common in patients with complex medication regimens. A systematic approach for identifying DDIs, determining clinical significance, formulating patient-specific recommendations, and communicating recommendations is important in pharmacy practice.