Drug replacement treatments: is amphetamine substitution a horse of a different colour?

Abstract

Advocates of amphetamine substitution therapy argue that needle sharing by amphetamine users, and associated infectious disease risk, outweigh the risks associated with oral dexamphetamine substitution prescribing, and that substitution can allow stabilization and gradual withdrawal of patients, or maintenance. Others note that amphetamine users are not generally physically dependent, dexamphetamine prescribing can lead to increased drug use and psychosis, and that there are possible neurotoxic effects from prolonged chronic exposure to amphetamines. Research on the impact of amphetamine and cocaine prescribing on drug use, injecting, social adjustment and criminal involvement is lacking apart from a small number of retrospective case reports. Early experience in the United Kingdom leads to the view that amphetamine maintenance was a therapeutic failure. More recently, clinicians have expressed confidence that the approach has merit, and while their claims should not be discounted there remains no empirical basis to support them. Although dexamphetamine substitution therapy has been heralded as an important intervention to reduce injecting behaviour and associated infectious disease risk, there is very little research which attests to its success in reaching this goal. Indeed, what is known regarding patterns of amphetamine use and the effects of prolonged use of the drug raise serious doubts as to the efficacy of amphetamine maintenance. There is an urgent need for randomized or case-controlled trails of the efficacy of these procedures. Until such empirical comparative research is available, the benefits to be gained from dexamphetamine substitution therapy remain speculative and opinion-based.