And the Answer Is...

Answer: Simvastatin

Combining multiple doses of 10 mg of amlodipine with 80 mg of simvastatin increased exposure to simvastatin by 77% compared with simvastatin alone, according to the FDA’s warning, which suggested limiting the daily dose of simvastatin to 20 mg in patients on amlodipine.

Use of simvastatin, one of the most common prescription medications in the older adult population, doubled from 10% to 22% among the elderly between 2005 and 2011, according to Dr. Dima M. Qato, the study’s lead author and an assistant professor in the College of Pharmacy at the University of Illinois at Chicago. She recently led a team of researchers who explored the use of prescription drugs, over-the-counter (OTC) products, and supplements among adults aged 62 to 85 years. The study revealed that polypharmacy — defined by the researchers as the concurrent use of at least 5 prescription medications — increased from 30.6% to 35.8% between 2005 and 2011. Statins use jumped from 34% to 46% during the study period, and 15% of patients were at risk of potential drug-drug interactions in 2010-2011, likely because of a significant increase in the use of dietary supplements during that time.

Dr. Qato said polypharmacy isn't always harmful, but there’s always potential for it to endanger patients, particularly for medication combinations with known drug interactions. She said providers need to discuss with patients the risks and benefits of all of their medications, and patients should reciprocate by keeping pharmacists and physicians constantly informed of all the medications they’re taking. Dr. Qato also suggested pharmacists should inform patients of potentially dangerous drug combinations when they’re taking medications that could interact with other prescription drugs, OTC products, and supplements.

—Dan Cook