Scientists are first to study toxic effects of BZP
"It's a rare drug now, MDMA. There are hundreds of thousands of tablets in circulation in the UK that look like ecstasy tablets, but which actually contain piperazines (a class of compounds that includes BZP).
The tablets are still being sold as ecstasy and because they have an effect, young people may think they are taking ecstasy."
"Before our research there had been no systematic study of the toxicity of these drugs and this is needed if we are to treat drug users effectively and inform people of the potential hazards associated with taking them."
"It was found that BZP itself is toxic to the kidney whilst the starting material, piperazine hexahydrate, showed toxicity in only the liver. In general the study showed that water soluble drugs, impurities and mixtures were toxic to liver cells, whilst compounds and mixtures which are fat soluble are toxic to the kidney.
"Mixtures of drugs and impurities, synthesised to reflect street samples, produced a variety of toxic effects depending upon the composition of the mixture - but all were significantly toxic.
"The work is important because it begins to provide an explanation of why people who have taken these drugs exhibit the symptoms that they do in A&E rooms.
"It also shows that different batches of drugs will have different effects because of the different proportions of drug and impurity in the material, and that users are exposed to toxic mixtures of drugs for which both the short and longer-term effects will not be known and cannot easily be predicted."
Addictions expert Sarah Graham, who is a spokesperson for the Government drugs helpline FRANK, said: "BZP is not safe - it is an entirely synthetic party drug which mimics the effects of ecstasy and speed. It is a stimulant which can raise your blood pressure and may lead to a fit or heart attack.
"You never know what you are getting because the chemical make up continually changes and mixing the drug with alcohol can increase the risks."