Ephedra is a Chinese shrub which has been used in China for medicinal
purposes for several thousand years. The pure alkaloid ephedrine was first isolated
and characterised by Nagai in 1885. It was then forgotten until it was rediscovered
by Chen and Schmidt in the early 1920s. Its actions on the adrenoceptors could
be classified into separate alpha and beta effects – a defining moment in the history
of autonomic pharmacology. Ephedrine became a highly popular and effective
treatment for asthma, particularly because, unlike adrenaline (until then the standard
therapy), it can be given by mouth. Ephedrine as a treatment for asthma reached its
zenith in the late 1950s, since when there has been a gradual and inevitable decline
in its therapeutic use. From mainstream medicine, ephedrine moved into the twilight
zone of street drugs and nutritional supplements. Ephedra and ephedrine products
are now banned in many countries, as they are a major source for the production of
the addictive compound methamphetamine (crystal meth).
