Chinese Herbal Medicines – Comparison of Doses Prescribed in Clinical Practice and those in China Pharmacopeia

Purpose: To compare the optimum doses of frequently used Chinese herbal medicines in clinical practice with stipulated doses in China Pharmacopoeia 2010, and assess the factors influencing choice of dose.
Methods: A total of 303 practitioners of traditional Chinese Medicine (TCM) from 50 comprehensive TCM hospitals were investigated using a multi-stage randomized questionnaire. The content of the questionnaire included doses of frequently-used Chinese herbs, cognition of current doses in clinical practice, and doctors’ (practitioners’) opinions on dose levels. The median of Chinese herbal medicines’ dose prescribed by the participants was compared with the upper limit value (ULV) of stipulated doses in China Pharmacopoeia by assigned rank test. The centralized tendency of dose selection by TCM doctors’ was expressed as mean ± standard deviation. The top three factors influencing selection of dose were obtained using inclusion and exclusion criteria.
Results: Among the selected Chinese herbs, the doses of 32 herbs exceeded ULV of the pharmacopoeia, accounting for 57.14 % (32/56). The top three factors influencing dose choice were variety and quality of the herbs, mode of preparation, and herbal combination. Furthermore, due to varying quality of the medicinal materials, method of preparation, and clinical experience, the doses among the 303 TCM doctors’ also varied considerably.
Conclusion: There is a significant difference between the doses of herbal medicines prescribed by TCM doctors’ and the doses stipulated in China Pharmacopoeia. In most cases, the former doses are higher.

Keywords
Chinese herbal medicines; China Pharmacopoeia; Dose selection; Multi-stage randomized questionnaire