From the Canadian Medical Association Journal (CMAJ) media release: Mixing commonly used antibiotics with common blood pressure medications may cause hypotension and induce shock in older patients, requiring hospitalization, according to a study published in CMAJ (Canadian Medical Association Journal). “Macrolide antibiotics (erythromycin, clarithromycin and azithromycin) are among the most widely prescribed antibiotics, with millions of prescriptions dispensed in Canada each year” writes Dr. David Juurlink, Scientist at the Sunnybrook Research Institute and the Institute for Clinical Evaluative Sciences with coauthors. “The drugs are generally well-tolerated, but they can cause several important drug interactions.” This study was conducted among Ontarians 66 years and older who were treated with a calciumchannel blocker between 1994 and 2009. The researchers identified 7100 patients hospitalized for low blood pressure or shock while taking a calcium channel blocker. Treatment with erythromycin was found to increase the risk of low blood pressure almost 6-fold, while clarithromycin increased the risk almost 4-fold. In contrast, azithromycin did not increase the risk of hypotension.
