COMMUNITY PRESCRIBING FOR OPIATE DEPENDENCY

The historical medical response to opiate dependency was to prescribe the drug of dependency and then slowly reduce the prescription to zero over a period of time (typically months). This practice remains commonplace but is probably a relatively ineffective route to abstinence for the majority of patients. The difficulty with such regimes usually becomes apparent when the daily methadone dose is reduced below 20mg, following which the illicit use of heroin tends to become increasingly more frequent. The medical response at this point will either be to accept failure and continue the reduction or to increase the methadone dosage in an attempt to re-stabilise before re-commencement of reduction. The National Treatment Outcome Research Study (NTORS (Gossop M et al, 1999)), demonstrated that there was no significant difference in methadone dosage between groups on methadone reduction regimes and on methadone maintenance regimes. The implication of this finding is that most doctors prescribing reduction regimes are increasing methadone doses in response to street heroin use, and that abstinence is only achieved by a minority of patients who are prescribed reduction regimes.

When considering the numbers of patients achieving abstinence (at least for 1 day), detoxification (see section C4) rather than slow reduction appears to be superior. Approximately 13% of patients prescribed a slow methadone reduction regime will complete the reduction without relapse to heroin use, whilst the number completing community detoxification is in the region of 50% and in-patient detoxification 80%. Whilst there is no direct evidence that long-term outcomes differ significantly between these treatments, it would seem likely that patients who have experienced a period of abstinence at some point would have a better long-term prognosis than patients who have failed to achieve abstinence. Despite these findings, slow methadone reduction regimes remain a valid route to abstinence for some patients. If such a regime is to be prescribed then the following phases of treatment should be considered:

• Phase 1: stabilisation (see above).
• Phase 2: reduction from stabilisation dose down to 20mg methadone daily.
• Phase 3: completion of the reduction from 20mg methadone daily to zero.

PHASE 2

Plan the total duration of the reduction (often up to 6 months in total).Agree the initial rate of reduction of methadone - usually between 5 and 10mg per fortnight.

PHASE 3

Reduce the rate of reduction as agreed with the patient; as smaller doses are achieved, the rate of reduction can be as little as 1mg per fortnight. Consider the use of 'blinding' where the pharmacist is asked to keep the volume of dispensed methadone the same while the concentration is altered (i.e. the patient is 'blind' to the prescribed dose).

If the patient has occasional lapses to heroin use (once weekly or less), it may be appropriate to continue with the reduction. If lapses occur more frequently than once weekly, it will usually be necessary to increase the methadone dosage and review the overall management plan; it may become clear at this point that detoxification rather than slow reduction is the preferred route to abstinence.

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The above information is copyright of Dr Bruce Trathen MBBS MRCPsych (2006). ISBN 0-9545164-0-0. The author grants permission for these guidelines to be downloaded, copied and distributed freely, but does not grant permission for their sale.