An audit of the effectiveness of amphetamine isomer ratios as a marker of Dexedrine compliance in amphetamine abusers.

The effectiveness of using amphetamine isomer ratios to determine individual compliance with a Dexedrine (dexamphetamine, Celltech, Slough, UK) treatment regimen for the maintenance and detoxification from amphetamine abuse has been audited. The calculation of l/d-amphetamine isomer ratios in urine has been shown previously to provide an accurate method for determining the compliance of subjects prescribed dexamphetamine. This audit was performed on the results obtained subsequent to the analysis of 369 urine specimens collected from 87 subjects (26 female, 61 male), all prescribed dexamphetamine collected from January 1999 to December 2002. The analysis was performed using a chiral derivatizing agent in conjunction with a gas chromatograph fitted with a mass spectrometer. It was found that only 245 specimens (66%) were deemed to be from compliant subjects. Of the remainder, 60 (16%) were collected when subjects were apparently supplementing their dexamphetamine prescription with illicit amphetamine, and 66 (18%) were collected when subjects were apparently using primarily illicit amphetamine. In summary, a sensitive and specific technique has been developed and applied to the analysis of urine specimens obtained from those prescribed dexamphetamine to facilitate the monitoring of their compliance. It is hoped that this technique may continue to be used to audit further the treatment in these individuals in the future to optimize their management.