Use of Potentially Fatal Drug Combinations Climbs in Older Adults

The risk of mortality in older adults due to drug interactions is seemingly growing, with 1 in 6 using potentially deadly combinations of prescription drugs, over-the-counter drugs, and dietary supplements.

A recent study took a nationally representative sample of adults between 62- and 85-years-old to analyze the changes in medication use. Additionally, researchers conducted in-home interviews to accurately determine what each individual was taking.

The results of the study showed that the percentage of older adults who took at least 5 prescription medications increased from 30.6% in 2005 to 35.8% in 2011.

The implementation of Medicare Part D, changes in treatment guidelines, and increased availability of generic drugs are potential factors for the increase in medication use.

The drug simvastatin (Zocor) is used to treat high cholesterol with the potential to reduce the risk of heart attack and stroke. The generic version of Zocor became available in 2006, with data showing an increase from 51.8% to 63.7% over the same time period.

There was approximately 50% growth in the amount of people using multiple supplements. Omega-3 fish oils, a dietary supplement that has limited evidence of cardiovascular benefits, saw the largest increase with 4.7% in 2005 and 18.6% in 2011.

Within the study, 15 of the most commonly used medications and supplements were identified as potentially life-threatening drug combinations. In fact, almost 15% of older adults were reported to have used at least 1 of these combinations regularly, compared with 8% in 2005.

More than half of the combinations involved nonprescription medications or dietary supplements. Preventative cardiovascular medications, anti-platelet drugs, and supplements accounted for majority of the combinations.

“Many older patients seeking to improve their cardiovascular health are also regularly using interacting drug combinations that may worsen cardiovascular risk,” said researcher Dima Mazen Qato. “For example, the use of clopidogrel in combination with the proton-pump inhibitor omeprazole, aspirin, or naproxen -- all over-the-counter medications -- is associated with an increased risk of heart attacks, bleeding complications, or death. However, about 1.8% -- or 1 million -- older adults regularly use clopidogrel in interacting combinations.”

Additionally, researchers state that when treating older adults, healthcare professionals should take into account the adverse effects of commonly used prescription and nonprescription medication combinations.

“Improving safety in the use of interacting medication combinations has the potential to reduce preventable, potentially fatal, adverse drug events,” Qato said.