Kava: A Risk-Benefit Assessment

In November 2001 the German Health Authority (BfArM; see Appendix 1 for abbreviations used) announced that it was intending to ban the use of kava ('Piper methysticum') because of reported cases linking kava consumption with hepatotoxicity. Despite submissions from manufacturers, therapeutic use of kava was banned altogether in Germany in 2002 and several other countries such as Japan, France, and Canada followed suit. Late in 2002 it was announced that the Medicines Control Agency (MeA) in the United Kingdom would also be banning kava; in February 2003 Swissmedic (formerly IKS) in Switzerland followed. At the time of writing, the Australian government is currently considering whether availability of therapeutic goods containing kava should be restricted. Since the action of the German authorities, government health administrations throughout the world have examined their databases for evidence of hepatotoxicity from kava use. Not surprisingly, more cases have come to light, but many of them are tenuous or inadequately reported. This chapter will review all known reported cases as of February 2003, with a view to arriving at an assessment as to whether the actions by the various health authorities have been justified. Much depends on the risk to benefit perspective. How much risk is acceptable for a herbal product? How good does the evidence need to be to arrive at a favourable risk-benefit assessment? The question must also be asked whether the interests of the consumer have been served by the complete banning of a herb that offered a viable alternative to conventional anxiolytic drugs, which are well known to have many risks associated with their use.