Songling Xuemaikang capsules for patients with low-to-medium risk hypertension: study protocol for a randomized controlled trial

BACKGROUND: Hypertension is a major risk factor for cardio-cerebrovascular disease. Songling Xuemaikang capsules (SXC), a formulation of Chinese herbal patent medicine, has been used as a complementary medicine with conventional western medicine to treat patients with hypertension since 1994 in mainland China. However, the efficacy of treatment with SXC alone against hypertension remains unclear. METHODS/DESIGN: This is a multicenter, placebo-controlled, double-blinded, randomized controlled clinical trial. A total of 570 patients with low-to-medium risk hypertension are randomized in a 1:1 ratio to receive SXC or placebo three times daily for eight weeks. The primary outcomes are 24-h average systolic blood pressure and average diastolic blood pressure. The secondary outcomes are daytime average blood pressure, night-time average blood pressure, fluctuation of blood pressure, hypertension control rate, traditional Chinese medicine (TCM) syndrome scores, and quality-of-life scores. DISCUSSION: This is the first multicenter trial conducted to evaluate the efficacy and safety of TCM in patients with low-to-medium risk hypertension. Our study will provide evidence-based results of a complementary preventive measure for hypertension. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR-IPR-17011383. Registered on 12 May 2017. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13063-019-3308-5) contains supplementary material, which is available to authorized users.