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Antihistamines, muscle relaxants linked with ED visits, mortality in elderly veterans

Exposure to skeletal muscle relaxants and antihistamines are linked to an increased risk for ED visits, hospitalization and death among the elderly, according to a recently published study.

“Despite the fact that these medications are listed an inappropriate to use in elderly patients, we found the incidence of antihistamine exposure to be 1.7% and skeletal muscle relaxant exposure to be 1.5%,” Carlos A. Alvarez, PharmD, MSc, of the Pharmacy Practice Department at Texas Tech University Health Sciences Center, and colleagues wrote.

To assess the association between muscle relaxants or antihistamines with mortality, hospitalizations and ED visits, researchers conducted a new-user, retrospective cohort study of elderly veterans (n=1,807,404). They utilized national Veterans Affairs administrative data from 128 hospitals, with inclusion of patients aged 65 years or older on Oct. 1, 2005, who had received VA inpatient or outpatient care at least once during the 2005 and 2006 fiscal years.

Among the patients evaluated via propensity-matched scoring for muscle relaxant use (n=55,566) and antihistamine use (n=60,058), the rate of mortality was lower in relaxant-exposed patients (adjusted OR=0.87; 95% CI, 0.81-0.94) at 1 year. Patients who were prescribed muscle relaxants, however, had a higher risk for emergency care (aOR=2.25; 95% CI, 2.16-2.33) and hospitalization (aOR=1.56; 95% CI, 1.48-1.65) at the same point.

Patients exposed to antihistamines had higher mortality (aOR=1.93; 95% CI, 1.82-2.04), ED visits (aOR=2.35; 95% CI, 2.27-2.43) and hospitalization (aOR=2.21; 95% CI, 2.11-2.32) rates at 1 year.

Primary outcomes of death, ED visits or hospitalizations within 1 year of study entry was seen in 17.7% of the cohort.

“Further interventions need to be developed to identify patients at high risk for events and reduce exposure to these medications while still providing acceptable substitutes for patients,” Alvarez said.

Disclosure: The researchers report no relevant financial disclosures.