New RCGP guidance on buprenorphine (Subutex) to treat opioid addiction

Heroin addiction has made significant inroads into country towns and rural communities in the UK . Specialist services for addicts tend to be inadequate or distant in our country areas so addicts who want treatment will be reliant on country doctors willing to train for and prescribe substitute therapy such as methadone or buprenorphine (Subutex). In recent years there has been a drive to encourage GPs, rural and urban, to treat patients with addiction problems and to share the care of such patients with the specialist agencies.

Alternative to methadone

Methadone-based treatment has been the traditional approach encouraged. Yet in other countries GPs have had large experience with the partial agonist buprenorphine. In France , for instance, it is prescribed by GPs 14 times more commonly than methadone. Buprenorphine, licensed for use in opioid dependency in the UK in 1999, is an alternative to methadone as a first-line treatment and can be used for maintenance or detoxification. It is a partial opioid agonist, appears safer in overdose than methadone and may have an easier withdrawal phase. It exerts sufficient opiate effects to prevent or alleviate opioid withdrawal, but produces a milder, less euphoric and less sedating effect than high doses of heroin, methadone or morphine.

The French experience indicates that in 1998 the death rate per patient treated with methadone was 0.0007 compared with 0.0002 for buprenorphine(1).  This means that if all patients in France received methadone instead of buprenorphine the expected number of deaths would have been 288 instead of 46 (1). So perhaps, in the UK ,  the tendency to reach automatically for methadone should receive increased scrutiny for this as well as other reasons.

RCGP new guidance available in 2004

The Royal College of General Practitioners produced ‘Guidance for the use of buprenorphine for the treatment of opioid dependence in primary care’ in 2003. This has now been revised to take account of new evidence and experience in the use of the drug and will be available in September 2004. The guidance is useful for GPs, nurse specialists and pharmacists and includes patient-specific information on the drug that can be photocopied and given to the patient. 

The Guidance agrees that buprenorphine is a useful alternative substitute medication for opioid dependent people. Buprenorphine widens the choice for opiate users who do not want methadone or who are intolerant of it. It may be considered as a first choice for people dependent on opioids who wish to become opiate free.

Methadone or buprenorphine?

The decision on  which medication to use should be made in consultation with the patient after considering the advantages and disadvantages of each medication for that patient. However, patients already doing well on either treatment should remain on their medication. Those not doing well may benefit from transferring to the other medication. Evidence of  buprenorphine’s superiority  or inferiority to methadone is equivocal. There is limited evidence of the superiority of either medication for particular subgroups.

The Guidance says that the consensus ‘among clinicians experienced in choosing both buprenorphine and methadone’ is that* (2):

• ‘Buprenorphine may be better suited to those who wish to cease using heroin completely, as the blockade effects of even moderate dose buprenorphine interfere with the subjective effects of additional heroin use. In contrast, whilst high dose methadone treatment is also well suited to those who wish to stop using heroin, those patients who wish to continue to use heroin may prefer low dose methadone treatment.’
• ‘Withdrawal from buprenorphine appears to be easier than from methadone, and as such may be preferred for those considering a detoxification program.’
• ‘The transition from buprenorphine to naltrexone can be accomplished much earlier than the transition from methadone to naltrexone, and consequently those considering naltrexone treatment after detoxification may be better suited to buprenorphine.’
• ‘Buprenorphine is less affected by interactions with hepatic enzyme inducers/ inhibitors (anti-convulsants, rifampicin, ribavirin).’
• ‘Buprenorphine is less sedating than methadone. This may be positive or negative for different patients.’
• ‘Using buprenorphine alone is safer in overdose.

*RCGP guidance quotes correct at time of writing

 The Guidance notes that although the cost of buprenorphine is more than methadone, buprenorphine is a schedule 3 drug and so attracts a lower dispensing fee than methadone. In addition, a study in Australia shows that when costs relevant to the provision of treatment are included (e.g. staff costs), the differences in cost-effectiveness between buprenorphine and methadone were not statistically significant (3).

The full guidance will be available at www.smmgp.co.uk

For copies and information about training on buprenorphine and  other aspects of primary care based drug and alcohol treatment please contact:

Mike Murnane, Drug and Alcohol Misuse Training Programme

Royal College of General Practitioners

020 7173 6091

mmurnane@rcgp.org.uk

or Mark Birtwistle

Substance Misuse Management in General Practice

0161 866 0126

mark@smmgp2.demon.co.uk

References

1. Auriacombe M. Deaths attributable to methadone vs buprenorphine in France (letter). JAMA 2001;285(1): 45
2. Royal College of General Practitioners. Guidance for the use of buprenorphine for the treatment of opioid dependence in primary care. Royal College of GPs, 2004 (in press)
3. Doran CM  et al. Buprenorphine versus methadone maintenance: a cost-effectiveness analysis. Drug and Alcohol Dependence 2003 71(3):295-302

(25/8/04)