The concern is, older adults taking calcium channel blockers for high blood pressure could suffer dangerous drops in blood pressure if they are given certain antibiotics.
At issue are two common antibiotics, erythromycin and clarithromycin, which are sold in brands such as E-Mycin and Biaxin.
The study found combining erythromycin along with a calcium-channel blocker increased the risk of low blood pressure hospitalization up to 6 times. It increased the risk 4 times as much in patients combining clarithromycin with common blood pressure medications.
The risk has been known, but this is the first time it has been quantified.