Efficacy and safety of Compound Danshen Dripping Pills as an adjunct to conventional therapy for stable angina pectoris: an updated systematic review and meta-analysis of randomized controlled trials

Objective To systematically evaluate the efficacy and safety of Compound Danshen Dripping Pills (CDP) in the treatment of stable angina pectoris (SAP) and provide updated evidence regarding its clinical application. Methods A comprehensive literature search was conducted in eight electronic databases, including PubMed, Embase, Web of Science, Cochrane Library, CNKI, Wanfang Data, VIP, and SinoMed, from inception to 31 May 2026. Randomized controlled trials (RCTs) comparing CDP plus conventional therapy (CT) with CT alone or CT plus nitrates in patients with SAP were included. Primary outcomes included angina efficacy, electrocardiogram (ECG) efficacy, angina frequency, angina duration, and nitroglycerin consumption. Secondary outcomes included lipid profile, left ventricular ejection fraction (LVEF), and fibrinogen (FIB), while adverse events were assessed as safety outcomes. Meta-analysis was performed using Review Manager 5.4 and Stata 18.0, and the certainty of evidence was evaluated using the GRADE framework. Results A total of 93 RCTs involving 10,208 participants were included. Compared with CT alone, adjunctive CDP was associated with improvements in angina efficacy (RR = 1.26, 95% CI: 1.19–1.33), ECG efficacy (RR = 1.34, 95% CI: 1.19–1.51), reduced angina frequency (SMD = −1.32, 95% CI: −1.79 to −0.84) and duration (SMD = −2.51, 95% CI: -3.58 to −1.45), and increased LVEF (SMD = 1.30, 95% CI: 0.24–2.37). Compared with nitrates plus CT, CDP plus CT also demonstrated comparable or superior improvements in angina efficacy (RR = 1.11, 95% CI: 1.08–1.15), ECG efficacy (RR = 1.35, 95% CI: 1.30–1.40), angina frequency, lipid profile, FIB, and several functional outcomes. CDP was generally well tolerated, with no increased risk of adverse events compared with CT alone and a lower incidence than nitrate-based therapy. However, the certainty of evidence ranged from moderate to very low, mainly due to methodological limitations and inconsistency among included studies. Conclusion Current evidence suggests that CDP-containing regimens may improve symptomatic and functional outcomes in patients with SAP compared with CT alone or nitrate-containing regimens; however, the certainty of evidence remains limited, and well-designed RCTs are needed to confirm these findings. Systematic Review Registration https://www.crd.york.ac.uk/PROSPERO/myprospero , Identifier CRD420261416404.