Prescription drugs including zolpidem are linked to emergency room visits, reports Modern Healthcare.

Though antipsychotics and antidepressants were the leading causes of the visits among adult patients between ages 19 and 44, sedatives and anxiety drugs were implicated in 38% of the visits for patients between ages 45 and 64, and 55% of the ED visits among patients 65 and older. The commonly used sedative, zolpidem tartrate, was implicated in 11.5% of all adult ED visits and in 21% of visits involving adults 65 years or older. The rate was significantly higher than any other psychiatric medication, the study said. Falls and head injuries were often cited among the adverse events.

“We didn’t expect any one sedative to stand out that much,” Hampton said. The study did not investigate why the rates were higher; further studies are needed to investigate that aspect. Zolpidem tartrate is the active ingredient in Sanofi’s Ambien and other generic forms of the sedative. The drug manufacturer declined to comment on the findings, saying the report looked at all forms of zolpidem, of which branded Ambien is one. “Most of the zolpidem market is generic, and we do not comment on a study of drugs we do not make,” responded a Sanofi spokesperson in an email.