Medications

Drug interaction causes hypotension

The commonly used muscle relaxant tizanidine can lower blood pressure. Tizanidine is metabolized by the enzyme CYP1A2, and concurrent use of tizanidine and a CYP1A2 inhibitor, such as ciprofloxacin, greatly increases tizanidine plasma concentrations. Despite package insert warnings, tizanidine and CYP1A2 inhibitors are commonly co-prescribed. Cecilia Chung, MD, and colleagues used electronic health records to […]