Effects of Danlou tablet for the treatment of stable angina pectoris A study protocol of a randomized, double-blind, and placebo-controlled clinical trial

Introduction: Stable angina pectoris has a high prevalence and causes serious harm. Revascularization therapy can relieve angina pectoris to some extent, but it is not widely accepted in China due to the cost and secondary events. The Chinese proprietary medicine Danlou tablet has been widely used to treat angina pectoris, but previous trials had inadequate methodologies. In this study, we aim to conduct a randomized controlled trial to evaluate its efficacy and safety on stable angina. Methods and analysis: This study is a WeChat-based randomized, double-blind, and placebo-controlled clinical trial in China. Eligible participants are adults (aged 30-75 years) with CT-confirmed stable angina and traditional Chinese medicine-diagnosed intermingled phlegm and blood stasis syndrome. A total of 76 participants will be randomly allocated in a 1:1 ratio to the oral Danlou tablet group (1.5 mg a time, 3 times daily for 28 days) or the placebo group. Patients are permitted concomitant use of routine medications during these 28 days. The primary outcome is angina frequency per week. The secondary outcomes include angina severity, angina duration, traditional Chinese medicine efficacy, the withdrawal rate of emergency medications, blood lipids, and electrocardiograph efficacy. The WeChat app will be used to remind patients to take their medicines and fill out the forms. All data will be recorded in case report forms and analyzed by Statistical Analysis System software. Ethics and dissemination: This study has been approved by the Ethics Committee of Guang'anmen Hospital, China Academy of Chinese Medical Sciences in Beijing, China (No. 2019-225-KY).