16 March 2005

Buprenorphine diversion prevalent in Victoria, rare in other states

Buprenorphine diversion and injection in Melbourne, Australia: an emerging issue? Jenkinson RA, Clark NC, Fry CL, Dobbin M. Addiction (2005) 100;2:197-205



Dear Colleagues,

When prescribed according to established guidelines, buprenorphine is very effective in retaining addicted subjects in treatment and in suppressing heroin use. This paper looks at buprenorphine from the 'grey' market perspective when supply does not meet demand by interviewing attendees at city needle exchanges in Melbourne.

We are told that of 156 subjects 57% had 'ever' used buprenorphine (53% in the previous 6 months). Of those reporting buprenorphine use, 37% reported obtaining the drug illicitly (i.e. not from their own prescription) at least once during that period with one quarter (26%) reporting 'mostly' using illicitly obtained buprenorphine (ie. not on their own prescription).

Of the 156, 37% had 'ever' injected buprenorphine (33% in the previous 6 months). Around half of these injectors had obtained sublingual tablets from illicit sources at least once and in one third of cases reported 'mostly using illicitly obtained buprenorphine'. Injectors were more likely to be poly drug users, to be in treatment (mostly bup), to be unemployed and to have a prison history (50%).

From these figures it would appear that for the previous 6 months for the 156 subjects, 31 (20%) had used illicit buprenorphine and 24 (15%) had injected illicitly obtained buprenorphine. Hence a quarter of the subjects involved in diversion had obtained illicit buprenorphine and NOT used it by injection. Thus Jenkinson, Clark, Fry, and Dobbin have demonstrated clearly that the mooted combination buprenorphine product (with naloxone to discourage injecting) cannot address this major aspect of diversion (illicit oral use). In addition, despite nearly 100% 'supervised' administration of this sublingual product there still appears to have been widespread 'leakage' to the community near these 5 needle programs. Take-home doses are apparently only allowed in exceptional circumstances in Victoria.

It is reassuring that 58% of these subjects who attended a needle exchange had been involved in some treatment in the previous 6 months. However, it may concern Victorian authorities that only 38% remained in treatment at the time of the questionnaire, implying that two thirds of these high-risk users had dropped out. Of those still in treatment, two thirds were taking buprenorphine, one third methadone and 3% drug-free treatment ('counselling').

This survey shows that even when there is widespread availability of buprenorphine from pharmacies, as in Melbourne, there is still a market for the diverted drug. This must be at least partly consumer driven and might reflect inadequate dose levels prescribed locally, inadequate dispensary opening hours, travelling, fees and/or other constraints in accessing prescribed buprenorphine.

From a purely public health perspective, this report might be seen as demonstrating a reduction in dependence on illicit, unhygienic and impure heroin for a pharmaceutical with quality control, labelling and predictability. However, some of the tablets may have been diverted after being in the oral cavity and thus could represent a serious infection risk. This might be termed a 'secondary treatment program' as in the concept of secondary needle programs which were reported recently. As with needles, it is still disappointing that the tablets were not available legally to those who needed them, when they need them (eg. before work for unskilled people starting at 7am; in lunch hours; evening doses for those doing overtime). While buprenorphine can last for 48 hours or longer in some situations, for new patients, reductions, pregnancy (not approved as yet) and fast metabolisers (half life as short as 9 hours in some - ref on request) it is not realistic to expect such people to work and function normally without having their daily medication first.

In response to the high rates of diversion, the authors remind us of the challenge to busy community pharmacists to strictly supervise the sub-lingual administration of the drug which can take over ten minutes in some cases. They even suggest the possibility of formal clinic treatment for some patients or else transferring to methadone to prevent diversion (a liquid is much easier to supervise).

The authors inform us that of the other five Australian jurisdictions for which comparable figures were taken for recent buprenorphine injecting, each was less than 5% (cf. 33% for this Melbourne sample). This is all the more remarkable since both Queensland and South Australia have allowed take-away dosing in parallel to methadone for stable patients for a number of years (up to 4 per week for those NOT on second daily dosing already). I understand that, apart from Perth, WA, the reported figures for subsequent years have not risen significantly. I have asked the Sydney injecting room staff about buprenorphine injecting and they say it is almost unheard of with heroin and cocaine making up the bulk (~95%) of their patients' dealings, in 'oscillating' proportions. Some Kings Cross police I have interviewed had never heard of the drug. Currently, there are about 2500 patients taking buprenorphine in New South Wales (pop ~ 6 million).

Congratulations to these authors for their vital seminal work. Thanks also to RAJ for her helpful suggestions and corrections for an earlier draft of this summary.

Comments by Andrew Byrne ..



Reference


Jenkinson RA, Clark NC, Fry CL, Dobbin M. Buprenorphine diversion and injection in Melbourne, Australia: an emerging issue? Addiction (2005) 100;2:197-205