Phytotherapy in treatment of benign prostatic hyperplasia: a critical review.

Phytotherapeutic agents have enjoyed widespread use, especially in Europe, for the treatment of BPH. With the recent proliferation of nutrition and vitamin stores in the United States, use of these agents has greatly increased. Although SPB extract is the most extensively studied of the phytotherapeutic agents used for BPH, no well-defined mechanism of action has been proposed. Evidence for an antiandrogenic or antiestrogenic effect is conflicting, and there are no clinical data suggesting an effect on 5-alpha-reductase activity. Furthermore, clinical trials with SPB have largely been uncontrolled and are thus of limited value in ascertaining the true clinical impact of this agent. Double-blind, controlled studies with SPB also have limitations in that most were of very short duration (none longer than 3 months) and did not provide entry or exclusion criteria. In addition, standardized symptom scores were not utilized. Only two of seven studies showed an appropriate placebo response, and the results and conclusions of both these studies were contradictory. The best and most convincing study of the efficacy of phytotherapeutic agents (using Harzol) was recently published in the Lancet. This study was rigorous and matched in design and format with pharmaceutical industry trials. A mild but appropriate placebo response was detected, which further validates the study. However, a prior placebo-controlled study showed no efficacy of beta-sitosterol-beta-D-glucoside. This dichotomy of results possibly reflects the different composition of the agents tested. This is a major confounding factor in this field of study, especially because the active ingredients are unknown. Standardization of the compounds is needed to compare and assess accurately the effect of the different extracts.