[The development from drug to designer drug].

Synthetic "designer drugs" with hallucinogenic properties have become increasingly popular among recreational drug users in recent years. Some of the designer drugs are chemically modified drugs previously used in treatment of depression and chronic fatigue. The drugs are available from a large number of internet distributers. There is very little knowledge of the clinical symptoms and how intoxicated people should be treated. We present a review of published literature (including 284 intoxicated patients) and experiences from the Danish poison centre concerning two chemical derivatives of earlier registered drugs.