Common roles and indications for pharmacotherapy in the treatment of substance misuse disorders include the following:

For those classes of substance which produce substantial physical withdrawal syndromes (alcohol, sedativehypnotics, opiates), medications are often needed to reduce withdrawal symptoms. Whilst opiate withdrawal is rarely life-threatening, alcohol and sedative-hypnotic withdrawal is associated with a significant mortality and morbidity rate if left untreated (see appendix 3, page 117 for characteristic withdrawal syndromes).

A widely used example of the use of medication for long-term stabilisation of drug users is methadone maintenance for opiate addicts, a treatment strategy which involves the daily administration of a long-acting opiate (methadone) as a substitute for the illicit use of a short-acting opiate (typically heroin). This permits the patient to function without experiencing withdrawal symptoms, craving or side-effects. Another example is nicotine replacement (patches, gum etc.) which effectively provides nicotine while minimising other harmful effects of smoking. This rationale is known as 'harm-minimisation'.

The best example of this approach is the use of naltrexone, a long-acting opiate antagonist, to block the effects of opiate use. Un-reinforced opiate use allows extinction of relationships between conditioned drug cues and drug use.A naltrexone-maintained patient, anticipating that opiate use will not result in desired drug effects, may be more likely to learn to live in a world full of drug cues and high-risk situations without resorting to drug use.