Toxicological screening in heroin users: implications for management of drug misuse.

The toxicological screening of 200 urine samples from 55 known heroin users claiming to be abstinent revealed that in 18% of samples (24% of users tested) opiates were unexpectedly detected. Other substances, many of which were psychoactive drugs, were identified in 35% of samples. Cocaine was not detected in any samples. In addition, nicotine was found in 91% of users and caffeine in 44%. The data showed the presence of polydrug abuse in 29% of subjects and suggested there is an illegal supply of drugs originating from doctors' prescriptions. The requirement for more general use of toxicological screening and the implications of the results for management of drug takers in general practices are discussed.