Crack cocaine. Vials containing 'Crack', a potent, highly addictive derivative of cocaine. Crack is ingested by inhaling the vapour produced when the white crystals are heated. Cocaine is obtained from the leaves of the Erythroxylon coca plant. Cocaine was once used as a local anaesthetic, but due to its potential for abuse, it has been replaced with other anaesthetics. Cocaine interferes with the action of neurotransmitters in the brain, producing feelings of euphoria & increased energy. Regular abuse of this drug damages the nasal linings and leads to dependence. Psychosis may develop if high doses are taken. Overdose with crack or cocaine can cause seizures and cardiac arrest.