Antihypertensive treatment: should herbal therapy be recommended?

Description

Worldwide herbal medicine is commonly used in the treatment of hypertension as for other cardiovascular diseases. The reasons include tradition and low price compared to modern antihypertensive drugs. Evidence for effectiveness in the form of clinical trials is, however, in general lacking (Ernst E, Wien Med Wochenschr. 2005; 155: 386-391). The concept that herbal drugs, with a wide spectrum of effects, might have advantages over modern hypertensive drugs is not erroneous: modern drugs that have specific effects often have to be used in combination. For example, angiotensin converting enzyme inhibitors usually have better effect if combined with diuretics. A herbal medicine that we have investigated, Randia siamensis, a climbing tree of the subfamily Gardennieae, family Rubiaceae, is also used for treatment of a wide variety of diseases including hypertension. In vivo and in vitro experimental studies on extracts of the fruit of R. siamensis show, however, that the drug has both hypotensive and hypertensive actions (R. Khwanchuea et al., Biol. Pharm. Bull., in press). Thus the mechanism of any clinical antihypertensive effect, if it truly exists, is likely to be complex. In contrast to these uncertainties regarding the effectiveness of herbal medicine, modern antihypertensive drugs can normalize blood pressure and with no or minimal side effects. This emphasises the importance of doing clinical trials if further effort is to be made on the use of herbal medicine in the treatment of hypertension. Where effect is demonstrated, it may then be worth identifying the active substances to determine the extent to which these alone or in combination are able to reduce blood pressure.