A few powerful meds can cause big problems

Four common medications are responsible for the majority of adverse drug reactions in older Americans, a study just published in The New England Journal of Medicine has found. Blood thinners and diabetes medications were responsible for 67 percent of emergency hospitalizations in people over the age of 65. And among blood thinners, anti-platelet drugs including aspirin and Plavix led to a sizable fraction of those ER visits.

The study, which reviewed over 5,000 cases in the National Electronic Injury Surveillance System between 2007 and 2009, estimated that there were nearly 100,000 emergency hospitalizations for adverse drug reactions in adults over 65 during this time period. The cases represented just 1.3 percent of all hospitalizations, but since these drugs are ubiquitous among older Americans, both health care providers and patients should be aware of the potential danger.

In particular, the blood thinner warfarin (Coumadin) was responsible for 33 percent of the cases, while insulins were associated with 14 percent. Another 13 percent was composed of reactions to aspirin, clopidogrel, and other antiplatelet drugs, and 11 percent was caused by oral hypoglycemic (diabetic) agents. Over all, digoxin, a widely prescribed drug for heart conditions, caused the highest percentage of ER visits resulting in hospitalizations. The findings suggest that the main problems caused by these drugs were bleeding and changes in mental status, ranging from confusion to siezures and loss of consciousness; the most common reason was inadvertent overdose.

These are drugs that are important in the treatment of life-threatening diseases, says ACSH's Dr. Gilbert Ross, but they have to be monitored closely and doctors must be aware that most of their older patients are on multiple medications with multiple potential interactions. Bleeding is often obvious, but diabetics should be alerted to the less obvious signs of low blood sugar, and have high-sugar snacks available in case of diminished mental function or dizziness.