The authors speculate that pharmacogenomic testing can identify patients at higher risk for adverse events related to drug-drug and drug-gene interactions based on the 29-year-old man’s prescription list and gene testing results. Potential drug-drug interactions should also be investigated, and patients should be appropriately monitored for adverse reactions. Before performing pharmacogenomic testing, consider the severity of potential reactions, cost, and the possibility of using an alternative regimen that avoids the interaction of concern entirely. As more is learned about pharmacogenomics and the potential personalization of therapeutic regimens, clinical considerations that warrant testing should be evaluated on a regular basis to facilitate both resource stewardship and optimal patient care.