Researchers have estimated that many elderly people treated in U. S. hospital emergency rooms are given one or more potentially inappropriate medications.

Nearly 19.5 million older patients, or 16.8 percent of eligible emergency visits from 2000-2006, received one or more potentially inappropriate medications. Pain relievers and antihistamines, sometimes used as a sedative or anti-allergic, are among the most common drugs used in emergency visits, found a University of Michigan study, published in the journal Academic Emergency Medicine.

The large sample of approximately 470,000 emergency department and outpatient clinic visits, corresponding to a national estimate of about 1.5 billion total visits, allowed the researchers to determine the extent of the problem nationwide, said Dr. William J. Meurer, an assistant professor at the University of Michigan.

The study also said that potentially inappropriate medications are less likely to occur in visits to hospitals in the Northeast and twice as likely in other parts of the country.

The researchers further found that receiving a potentially inappropriate medication was more likely to occur at for-profit hospitals.

Ten medications accounted for 86.5 percent of potentially inappropriate medications used in the emergency room. The five most common ones were promethazine, ketorolac, propoxyphene, meperidine and diphenhydramine.

Adding further, the researchers said that the possibility of medication interactions was not explored by the study, so it is possible the potential harm by medications is underestimated. (With Inputs from Agencies)