Increase in plasma phylloquinone concentrations following acupoint injection for the treatment of primary dysmenorrhea.

The therapeutic benefits of acupoint injection of vitamin K in spleen-6 (SP6) for the treatment of primary dysmenorrhea have been observed in limited clinical settings. However, menadione, the form of vitamin K most studied for treating dysmenorrhea, is not routinely used in clinical practice in North America. As part of a larger clinical trial among women aged 18-25 years with primary dysmenorrhea, we conducted a substudy to test the plasma concentration of phylloquinone (vitamin K1). We collected blood samples from four women before and 24-48 hours after an acupoint injection of phylloquinone in SP6. Despite the rapid turnover of phylloquinone observed in previous studies, we found that the plasma phylloquinone concentrations increased significantly from preinjection to 1-2 days after the injection. Interestingly, higher phylloquinone concentrations were correlated with less pain intensity among women with dysmenorrhea. Additional research is needed to understand the association between vitamin K and menstrual pain, including the role of vitamin K deficiency in inflammation and pain, and on the possible mechanisms of acupoint injection of vitamin K for the treatment of primary dysmenorrhea.