Effects of echinacea on electrocardiographic and blood pressure measurements

The effects of Echinacea purpurea on electrocardiographic and blood pressure measurements in healthy volunteers were evaluated.

Healthy volunteers were randomized to receive a single 350-mg dose of E. purpurea or placebo in a crossover fashion with a seven-day washout period between treatment phases. Twelve-lead electrocardiograms were acquired, and systolic and diastolic blood pressure measurements were taken immediately before (baseline) and at one, three, five, and eight hours after ingestion of the study drug. Electrocardiographic variables (P wave and QRS complex duration and PR, Q-T, Q-Tc, and RR intervals) were measured in lead II by one blinded study investigator. Duplicate blood pressure determinations were taken manually at each time point and then averaged. The maximum posttreatment values, irrespective of time point, for each electrocardiographic and blood pressure measurement were compared between groups.

Of the 17 healthy adults initially screened for this study, 16 completed both phases. There was no difference in maximum posttreatment electrocardiographic or blood pressure (systolic or diastolic) variables noted between groups. Mild headache was reported by one patient receiving echinacea and one receiving placebo. One participant receiving echinacea experienced shortness of breath five hours posttreatment and mild flu-like symptoms after eight hours; symptoms completely resolved over the next several days.

A single 350-mg dose of E. purpurea had no effect on electrocardiographic and blood pressure measurements of healthy volunteers.