A wave of killer designer drugs is sweeping the country as narcotics peddlers use science to stay ahead of the law. As quickly as laws are enacted to outlaw new drugs, manufacturers are tweaking the formulation of their products to evade the law - and this fine-tuning is sowing death among schoolchildren.Tshwane, battling the scourge of nyaope [dagga mixed with heroin], now faces an even more lethal narcotic - monopi, which has claimed the lives of 20 people .KwaZulu-Natal is in the grip of a deadly designer drug called Mercedes that has killed 11 people since March.A team of police crime intelligence officers was establish ed after Police Minister Nathi Nhleko and Minister of Justice, Constitutional Development and Correctional Services Michael Masutha were briefed about Mercedes.It sells for R30 a pill and is called Mercedes because it is said to leave its users "as high as if they were driving the German car".Also known as umgwinyo, "data" or "music", laboratory tests show that Mercedes contains n-ethylpentylone, which is also found in the illegal narcotic cathinone.Monopi is a mixture of low-grade crystal methamphetamine, or tik, cut with a variety of chemicals.Victor Tswayi, chairman of the Mamelodi Local Drug Action Committee, said monopi had killed 20 people in Mamelodi and Eersterust."Three weeks ago four people died from monopi."Thabo Kgotsi, manager of the Thandanani community project in Atteridgeville, said the drug, which costs between R20 and R50, was a "killer party drug".Lehlohonolo Letsoalo, head of the Aga Sechaba community anti-drug council, said monopi emerged two years ago and some as young as 12 were taking it.According to the Narcanon website, cathinones were included in the group of "designer drugs" - so called because all a chemist had to do to evade law enforcement was design a new molecule.Change the chemical structure in some tiny way and the seller can claim that it is a new drug.In the US and Europe there are hundreds of drugs in this and similar classes. Some of the dangers of using cathinones are hallucinations, delusions, psychosis and suicide...