Drug interactions have become a significant iatrogenic complication, with as many as 5% of hospitalizations and 7,000 deaths annually attributable to drug-drug interactions in the United States. There are several reasons these numbers have increased. First, many new medications have been brought to market in recent years. Second, advances in medical care have resulted in increased longevity and more elderly patients than ever before -- patients who are more likely to be following polypharmacy regimens. Population patterns in the U.S. have amplified this trend, with aging baby boomers...