Pharmacokinetics of cocaine: considerations when assessing cocaine use by urinalysis.

Changes in a patient’s patterns of cocaine use are generally considered an important outcome measure of treatment efficacy. Other treatment outcome measures are important as well, but if a treatment does not stop or significantly decrease the intensity of a cocaine addict’s cocaine use, many would question the treatment’s efficacy. Examination of a patient’s urine for evidence of cocaine or cocaine metabolites is an objective index of cocaine use. Like many biochemical measures useful in medical practice, urinalysis to measure cocaine or its metabolites, although relatively simple and straightforward from an analytic standpoint, is subject to misinterpretation and erroneous conclusions if the underlying biological principles are not properly considered.