(CBCNews.ca) — Seniors taking common blood pressure medications could be at risk of being hospitalized for blood pressure that falls too low if they are taking a certain type of antibiotic, a new Canadian study suggests.
The study focused on drug interactions involving calcium channel blockers and macrolide antibiotics such as erythromycin, clarithromycin and azithromycin, which are among the most widely prescribed medications in Canada, the researchers said.
“The [macrolide antibiotics] are generally well-tolerated, but they can cause several important drug interactions,” said Dr. David Juurlink, scientist at the Sunnybrook Research Institute in Toronto and the Institute for Clinical Evaluative Sciences.
In Monday’s issue of the Canadian Medical Association Journal, Juurlink and his co-authors analyzed medical records of nearly one million Ontario residents aged 66 and older who were prescribed calcium channel blockers for hypertension, including 7,100 who were admitted to hospital with shock or hypotension — low blood pressure.
“Our findings highlight the consequences of an under-appreciated yet avoidable drug interaction involving medications used by millions of patients every year,” the researchers wrote.
In the study, researchers compared whether a macrolide antibiotic had been prescribed a week before the hospitalization versus an earlier time frame when they weren’t prescribed the antibiotic.