Bad reactions to psychiatric drugs result in nearly 90,000 emergency room visits each year by U.S. adults, with anti-anxiety medicines and sedatives among the most common culprits, a study suggests.
A drug used in some popular sleeping pills was among the most commonly involved sedatives, especially in adults aged 65 and older.
Most of the visits were for troublesome side-effects or accidental overdoses and almost 1 in 5 resulted in hospitalization.
The results come from an analysis of 2009-2011 medical records from 63 hospitals that participate in a nationally representative government surveillance project. The study was published Wednesday in JAMA Psychiatry.
Overall, the sedative zolpidem tartrate, contained in Ambien and some other sleeping pills, was involved in almost 12 per cent of all ER visits and in 1 out of 5 visits for older adults. Zolpidem tartrate is approved for use as a sleep aid by Health Canada.
The U.S. Food and Drug Administration last year approved label changes for those pills recommending lower doses because of injury risks including car crashes from morning drowsiness. Head injuries and falls in adults using zolpidem-containing drugs were among reasons for ER visits in the new study.
In January, Health Canada said it endorsed lower dosing instructions for Sublinox or zolpidem tartrate to minimize risk of next-day impairment.
Sanofi, the pharmaceutical company that makes Ambien, includes a warning in its prescribing information that says the drug can cause "impaired alertness and motor co-ordination." It also says doctors should "caution patients against driving and other activities requiring complete mental alertness the morning after use."
Sanofi issued a statement Wednesday after the study was published noting that the FDA approved Ambien in 1992 based on data showing the drug is safe and effective.
Drs. Lee Hampton and Daniel Budnitz of the U.S. Centers for Disease Control and Prevention's health care quality promotion division led the study. The authors cited previously published national data showing that ER visits for bad reactions to zolpidem increased 220 per cent from 2005 to 2010.
"The FDA's recent efforts to modify recommended dosing regimens hold promise" for reducing zolpidem-related problems, the authors said. But they also said doctors can help by recommending that patients use other insomnia treatments first, including better sleep habits and behaviour therapy.
Bad reactions to other psychiatric medicines in the study included mental disturbances, heart-related symptoms and intestinal problems.
The study notes that nearly 27 million U.S. adults used prescription drugs to treat mental illness in 2011, so only a fraction of them had bad reactions resulting in ER treatment. Still, the authors say doctors need to weigh the benefits and risks before prescribing psychiatric medicines.