Efficacy and safety of Shexiang Tongxin pill for coronary slow flow in angina patients

Previous preclinical studies suggested that Shexiang Tongxin Dropping Pill (STDP) would be effective for coronary slow flow phenomenon (CSFP), but its clinical efficacy and safety remain uncertain. A multicenter, randomized, controlled phase IV trial was implemented to enroll 200 participants diagnosed with angina and CSFP between July 2016 and August 2020 to examine the drug's effectiveness and safety. The analysis revealed that corrected TIMI frame count (CTFC) values in left anterior descending (LAD) and left circumflex (LCX) arteries in STDP group could be decreased, respectively (both p < 0.01), whereas no significant changes were seen with placebo; between group differences were significant for both LAD (p = 0.008) and LCX (p = 0.044). Furthermore, STDP was well tolerated. Taken together, the results demonstrated STDP could significantly improve coronary blood flow and maintain an excellent safety profile, making it a favorable option in clinic for angina patients with CSFP. Trial registration: The trial was registered in Chinese Clinical Trial Registry (ID: ChiCTR-IPR-16008950).