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Article Excerpt
Introduction
Buprenorphine, a partial mu receptor agonist, has been available as a substitution therapy for opiate dependence in Australia since 2001 (Ali, Biggs, Dorlego, Gill, Larkins, Moyle, et al. 2001). Since its introduction buprenorphine has been a popular alternative to methadone maintenance therapy, as its long elimination half-life and the tightness of binding to its receptor eliminate the need for daily dosing (Elkader & Sproule, 2005). Additionally, due to its partial agonist effects, buprenorphine is less intoxicating and less addictive than methadone, a full agonist. Buprenorphine is marketed as a sublingual preparation, (Subutex[R]-buprenorphine hydrochloride) as its low oral bioavailability would cause it to be rapidly metabolized if ingested (Elkader & Sproule, 2005).
Buprenorphine exhibits a plateau in the dose-response curve on its physiological and subjective effects, and is therefore regarded as having a low abuse potential (Davids & Gastpar, 2004; Walsh, Preston, Stizer, Cone & Bigelow 1994; Wesson, 2004). Despite this, cases of buprenorphine abuse have been documented since as early as 1984, when buprenorphine was available as a low-dose analgesic. Quigley and Collegues described a 24 year old opiate-dependent individual who intravenously injected buprenorphine as an alternative to heroin, claiming it had similar effects but was less expensive and easier to obtain than heroin (Quigley, Bredemeyer & Seow 1984). Considerable misuse of low-dose buprenorphine has also been reported in New Zealand (Robinson, Dukes, Robinson, Cooke & Mahoney 1993) and the use of low-dose buprenorphine in buprenorphine-temazepam cocktails was prevalent in Scotland in the early 1990s (Forsyth, Farquhar, Gemmell, Shewan & Davies 1993; Hammersley, Cassidy & Oliver 1995).
Numerous articles have described diversion and injecting misuse of buprenorphine in India (Basu, Mattoo, Malhotea, Gepta & Malhotra 2000; Chowdhury & Chowdhury, 1990; Singh, Mattoo, Malhotra & Varma 1992), Singapore (Winslow, Ng, Mythily, Song & Yiong 2006) and France (Obadia, Perrin, Feroni, Vlahov & Moatti 2001; Varescon, Vidal-Trecan, Nabet & Boissonnas 2002; Vidal-Trecan, Varescon, Nabet & Boissonnas 2003). In a series of studies conducted in France, it was found that as many as 50% of all maintenance pharmacotherapy patients (buprenorphine or methadone) reported injecting buprenorphine at least once in their lifetime (Varescon, Vidal-Trecan, et al., 2002; Vidal-Trecan, Varescon, et al., 2003).
Beyond the risk of transmission of blood-borne viruses accompanying most injecting drug use, injection of drugs intended for oral use, such as Subutex[R], introduces additional health risks. This is due to inert components such as corn starch which, when injected, can lead to microvascular occlusions (Waller, Brownlee & Roberts 1980; Woodburn & Murie, 1996). Documented cases of parenteral abuse of Subutex[R] have included severe groin tissue necrosis due to Staphylococcus aureus infection (Feeney & Fairweather, 2003) as well as ischaemic injuries in the hands and upper limbs leading to gangrene and eventual amputation (Gouny, Gaitz & Yayssairat 1999; Loo, Yam, Tan, Peng & Teoh 2005). Furthermore, intravenous misuse of sublingual buprenorphine tablets has been implicated in jaundice and severe hepatitis episodes in patients with chronic hepatitis C (Berson, Gervais, Cazals, Boyer, Durand, Bernuay, et al., 2001). More recently, several cases of fungal eye infections resulting from injection of buprenorphine tablets that had been in the oral cavity and become contaminated with oral Candida species have been documented (Aboltins, Daffy & Allen 2005). This is a significant problem in the Australian state of Victoria as supervised dosing requires patients to place their buprenorphine in their mouth in the presence of a pharmacist. Despite this requirement, diversion and injection of "spitbacks" has reportedly become common in some parts of Victoria (Topp, 2006).
To combat buprenorphine diversion a new formulation of buprenorphine has recently been introduced in Australia. Suboxone[R] combines buprenorphine hydrochloride with an opioid antagonist, naloxone hydrochloride, which has a poor oral bioavailability and thereby no antagonist effect when consumed sublingually (Stoller, Bigelow, Walsh & Strain 2001) but will induce opioid withdrawal symptoms if injected by an opiate-dependent individual (Harris, Mendelson, Lin, Upton & Jones 2004). It is reasoned that the potential to induce withdrawals would be a major deterrent for IDUs from injecting Suboxone[R].
Recent literature has indicated that buprenorphine diversion and injection is an emerging issue in Australia, particularly in the state of Victoria, despite supervised dosing requirements (Aitken, Higg & Hellard in press; Jenkinson & O'Keeffe, 2004; Lintzeris, Ritter, Panjaci, Clark, Kutin & Bammer 2004; Mongan, 2006). Findings from recent Illicit Drug Reporting System (IDRS) surveys highlight a consistent increase in participants reporting recent (in the preceding six months) injection of their own ("licit") buprenorphine and of buprenorphine that had not been obtained via a prescription in their own name ("illicit" buprenorphine), from 6% and 9% respectively in 2003 to 11% and 14% respectively in 2005 (Breen, Degenhardt, et al., 2004; Stafford, Degenhardt, et al., 2005). The greatest prevalence of use of both licit and illicit buprenorphine has consistently been recorded in Victoria (Breen, Degenhardt, Roxburgh, Bruno, Fetherston, Jenkinson, et al., 2004; Jenkinson, Clark, Fry & Dobbin 2005; Stafford, Degenhardt, Roxburgh, Bruno, Fetherston, Jenkinson, et al. 2005); 63% of 2005 Victorian IDRS interviewees reported ever injecting buprenorphine, and 39% had done so in the previous six months (Jenkinson & O'Keeffe, 2006). Additionally, data from a recent survey of community pharmacists (n=24) in Victoria found that 8% of their patients had been caught attempting to divert their buprenorphine doses for either personal use, or for sale on the black market (Muhleisen, Panjari & Lee 2003). These community pharmacies were dosing 433 people, about 14% of all people being prescribed Subutex[R] in Victoria at the time.
Despite the rapid increase in patients being prescribed buprenorphine maintenance therapy and indications of an upward trend in buprenorphine misuse, Australian research on this topic thus far has been quantitative, intended to portray the extent of the phenomenon rather than to understand its drivers and meaning. Hence, the aim of the study described herein was to explore individual drug user's motivations for engaging in this behavior.
Methods
Semi-structured face-to-face interviews were conducted by Danielle Horyniak and Stuart Armstrong. Participants were required to be over 18 years of age and able to give informed consent, and to have injected buprenorphine at least once (but were not required to be regular injectors). Participants were recruited through Needle and Syringe Programs and through snowballing methods. Recruitment continued until respondents reflected a variety of ages, genders, and locations and until no new, distinct narratives were being identified. The final study group consisted of 16 participants from Frankston, a suburb 40 km south-east of Melbourne's Central Business District (CBD), three participants from Collingwood, 2 km north-east of Melbourne, and four participants from...
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