A sample of 312 heroin users was interviewed regarding the injection of methadone syrup. Methadone syrup injecting was widespread, with 52% of the sample ...
THE INJECTION OF METHADONE SYRUP IN SYDNEY, AUSTRALIA
Shane Darke, Joanne Ross & Wayne Hall
National Drug and Alcohol Research Centre 1995 Technical Report No. 30 ISBN
© National Drug and Alcohol Research Centre
TABLE OF CONTENTS ACKNOWLEDGMENTS .............. ........................ ........................ ........................ ........ vi EXECUTIVE SUMMARY .............. ........................ ........................ ........................ .......vii 1.0
INTRODUCTION .............. ........................ ........................ ........................ ......... 1
1.1
Study aims .... ........................ ........................ ........................ ........................ ...................... 2
2.0
METHOD .... ........................ ........................ ........................ ........................ ...................... 3
2.1
Procedure...... ........................ ........................ ........................ ........................ ...................... 3
2.2
Structured interview............ ........................ ........................ ........................ ......... 3 2.2.1 Demographic characteristics ............ ........................ ........................ ......... 3 2.2.2 Drug use history ........ ........................ ........................ ........................ ...................... 3 2.2.3 Heroin dependence... ........................ ........................ ........................ ......... 4 2.2.4 Health. ........................ ........................ ........................ ........................ ......... 4 2.2.5 Psychological functioning................. ........................ ........................ ......... 4 2.2.6 Heroin overdose ........ ........................ ........................ ........................ ...................... 4 2.2.7 Needle risk behaviours ..................... ........................ ........................ ...................... 4 2.2.8 Criminal behaviours . ........................ ........................ ........................ ......... 4 2.2.9 Initiation of methadone injecting .... ........................ ........................ ......... 5 2.2.10 Methadone injecting procedures .... ........................ ........................ ......... 5 2.2.11 Most recent methadone injection episode ............. ........................ ......... 5
2.3
Analyses........ ........................ ........................ ........................ ........................ ...................... 5
3.0
RESULTS ..... ........................ ........................ ........................ ........................ ...................... 6
3.1
Sample characteristics ......... ........................ ........................ ........................ ...................... 6
3.2
Drug use history ................... ........................ ........................ ........................ ............ ......... 7
3.3
Heroin dependence.............. ........................ ........................ ........................ ......... 9
3.4
Prevalence of methadone injecting ............ ........................ ........................ ......... 9
3.5
Frequency of methadone injecting ............. ........................ ........................ ....... 10
3.6
Characteristics of methadone injectors...... ........................ ........................ ....... 12 3.6.1 Demographics............. ........................ ........................ ........................ ....... 12 3.6.2 Area of residence........ ........................ ........................ ........................ .................... 12
3.6.3 Methadone maintenance ................... ........................ ........................ ...................... 1 ......... 4 3.6.4 Drug use history ......... ........................ ........................ ........................ .................... 15 3.6.5 Heroin dependence.... ........................ ........................ ........................ ....... 15 3.7
Initiation of methadone injecting ............... ........................ ........................ ....... 15
3.8
Methadone injecting procedures ................ ........................ ........................ ....... 17
3.9
Most recent methadone injection episode ........................ ........................ ....... 18
3.10
Correlates of methadone injecting ............. ........................ ........................ ....... 21 3.10.1 3.10.2 3.10.3 3.10.4 3.10.5
Health ........................ ........................ ........................ ........................ ....... 21 Heroin overdose ....... ........................ ........................ ........................ .................... 21 Psychological functioning ............... ........................ ........................ ....... 23............ Needle risk behaviours .................... ........................ ........................ .................... 23 Criminal behaviours ........................ ........................ ........................ ....... 23
3.11
Predictors of current methadone injecting ........................ ........................ .................... 23
4.0
DISCUSSION ...................... ........................ ........................ ........................ .................... 25 ...................
4.1
Major findings of the study ........................ ........................ ........................ ....... 25
4.2
Data validity and representativeness of sample ............... ........................ ....... 25
4.3
Prevalence of methadone injecting ............ ........................ ........................ ....... 26
4.4
Methadone injecting procedures ................ ........................ ........................ ....... 26
4.5
Methadone maintenance and methadone injecting ........ ........................ ....... 27
4.6
Area of residence and methadone injecting ...................... ........................ .................... 27
4.7
Sources of methadone for injecting ............ ........................ ........................ ....... 28
4.8
Harms associated with methadone injecting .................... ........................ .................... 28
4.9
Implications.. ........................ ........................ ........................ ........................ ....... 29
4.10
Conclusions .. ........................ ........................ ........................ ........................ .................... 29
5.0
REFERENCES ...................... ........................ ........................ ........................ .................... 31
LOCATION OF TABLES Table 1:
Demographic characteristics of 312 heroin users . ........................ ......... 7
Table 2:
Drug use history of 312 heroin users...................... ........................ ...................... 9
Table 3:
Prevalence of methadone injecting ........................ ........................ .................... 10
Table 4: Frequency of methadone injecting among current methadone injectors in preceding six months .. ........................ ........................ ........................ ....... 11
Table 5:Demographic characteristics of respondents who had injected methadone versus those who had not .... ........................ ........................ ................... Table 6:
Area of residence and methadone injecting .......... ........................ .................... 14
Table 7:
Circumstances of initial methadone syrup injection .................... ....... 16
Table 8:
Methadone syrup injection procedures ................. ........................ ....... 18
Table 9:
Circumstances of most recent methadone injection ..................... .................... 20
Table 10:
Correlates of current methadone injecting ............ ........................ ....... 22
Table 11:Multiple logistic regression predicting injection of methadone syrup in the preceding six months .... ........................ ........................ ...................
ACKNOWLEDGMENTS This research was funded by the Drug and Alcohol Directorate of New South Wales. The authors would like to thank the following organisations for their assistance in this study: Liverpool Hospital Drug and Alcohol Unit, Canterbury Hospital Drug and Alcohol Unit, Kullaroo Clinic, the Central Coast Needle Exchange, We Help Ourselves, St Mary's Needle Exchange and SWAP. In particular, we would like to thank Karen Becker, Mario Fantini, Bruce Flaherty, Anna Haining, Gayle Kennedy, Lisa Maher, Dorothy Oliphant, Suzanne van Opdorp, Helen Polkinghorn, Garth Popple and Sandra Sunjic.
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EXECUTIVE SUMMARY A sample of 312 heroin users was interviewed regarding the injection of methadone syrup. Methadone syrup injecting was widespread, with 52% of the sample having injected methadone syrup, 29% in the preceding six months. Males and females were equally likely to report having ever injected methadone syrup, and to have done so in the six months preceding interview. Among current methadone injectors, frequent methadone injecting was common, with 40% reporting weekly or more frequent injecting in the preceding six months. Methadone injecting was more common in western Sydney, both in lifetime prevalence (58% v 45%) and within the preceding six months (36% v 21%). Frequent injecting was also more common in the western suburbs. Recent methadone injecting was more common among respondents currently enrolled in methadone maintenance (34% v 23%). Both area of residence and treatment status were independent predictors of current methadone injecting. The two most common sources for obtaining methadone for injection were friends/partners or respondents' own prescribed take-away doses. Illicit methadone was considered easy to obtain by 87% of respondents. The average price of methadone was 50c per milligram in the western suburbs and $1 per milligram in other regions of Sydney. There were clear harms associated with methadone syrup injecting. Current methadone injectors were in poorer general health than other respondents, and had more symptoms related to injecting. A history of methadone injecting was associated with abscesses and infections in injection sites, and having been diagnosed with a venous thrombosis. Those with a history of methadone injecting were also more likely to have overdosed (70% v 52%), with current injectors being more likely to have overdosed in the preceding six months (26% v 14%). Current methadone injectors also showed higher levels of current psychological distress, were more likely to have recently passed on used injecting equipment and to have recently committed criminal acts. The results of the present study raise questions about ways in which to reduce the harms associated with methadone syrup injecting. Issues that require attention include: policies on the provision of take-away methadone doses; strategies such as diluting methadone syrup to expand the volume of a methadone dose; and education of methadone maintenance clients on the harmful effects of methadone injecting.
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1.0 INTRODUCTION Orally delivered methadone maintenance has been repeatedly demonstrated to be the most cost effective, efficacious treatment for opioid dependence1. Enrolment in methadone maintenance had been associated with reduced frequency of injecting, reduced frequency of needle sharing, a reduced risk of HIV infection and a reduced risk of heroin overdose1,2. Methadone maintenance services have expanded rapidly in Australia since 1987, with approximately 17,000 people now enrolled on methadone maintenance3. A great deal of recent clinical concern has arisen, however, about the injection of methadone syrup. Anecdotal evidence has linked this practice to the western suburbs of Sydney in particular, with needle exchanges in this region reporting an increased demand for 10 ml and 20 ml syringes and vein infusion sets, equipment thought to be employed to inject methadone syrup. The major health concern raised by the injection of methadone syrup is the development of venous thrombosis. The viscous nature of the syrup makes it difficult to inject and, as such, greatly increases the risk of thrombosis after delivery into the vascular system. It should be noted that the development of thrombosis has also been associated with injection of temazepam capsules, like methadone a viscous liquid4,5. Direct damage arising from repeated injections with large gauge needles is also of concern, with cases of fistulas having been reported to have arisen from the repeated injection of methadone syrup6. Repeated injections may be necessary in order to inject the large volume of methadone syrup and water needed for intoxication. The use of large sized syringes to inject methadone is also a cause for concern in relation to the spread of blood borne viruses. It has been shown that the risk of passing on blood through needle sharing substantially increases as the size of the syringe increases7. These authors estimated that 10 times more blood is transferred when using a 2 ml syringe as opposed to the more common 1 ml syringe. The use of 10 ml and 20 ml syringes for methadone syrup injections clearly would exacerbate this problem if needles were being shared. Despite these concerns, to the authors' knowledge, no study on the illicit injection of methadone syrup has been conducted to date in Australia. Several studies outside Australia have reported on the use of illicit methadone, but these have not focussed on the injection of methadone syrup8-12. Inciardi8, in 1977, reported 46% of a large sample of U.S. heroin users had used illicit methadone during the week prior to interview, with 70% of respondents having used illicit methadone in the three months prior to interview. Daily use of methadone was rare, with 5% of respondents reporting daily use in the preceding three months, 40% weekly or more frequent use, and 55% less than weekly use. No data on route of administration was provided. Weppner et al12
1
reported a lifetime prevalence of illicit methadone use of 43% among patients admitted to Lexington hospital for opiate detoxification. Sapira et al10 reported in 1968 on 25 methadone dependent males admitted to Lexington hospital. Less than half (36%) of these patients used methadone orally, with 40% using intravenously and a further 24% intramuscularly. A third (34%) of methadone patients interviewed in Spunt et al11 reported having ever diverted their methadone dose. More recently, Lauzon et al9 reported a lifetime prevalence of illicit methadone use of 59% among a sample of Canadian heroin users. In the six months preceding interview, 42% of these respondents reported having used illicit methadone. No data were given on route of administration. The current study aimed to provide data on the prevalence of methadone syrup injecting among a sample of Sydney heroin users, and the procedures and problems associated with this practice. 1.1 Study Aims The major aims of the study were as follows: 1)To determine the extent of methadone injecting, and the factors associated with it; 2)To examine methadone injecting procedures; 3)To examine problems associated with the injection of methadone.
2
2.0 METHOD 2.1 Procedure All respondents were volunteers who were paid A$20 for their participation in the study. Recruitment took place from January to October of 1995, by means of advertisements placed in rock magazines, a users group magazine, needle exchanges, methadone maintenance clinics and by word of mouth. Respondents contacted the researchers, either by telephone or in person, and were screened for eligibility to be interviewed for the study. To be eligible for the study respondents had to either be in treatment for heroin dependence, or have used heroin during the preceding three months, or both. Those respondents who had injected methadone were questioned in detail about their experience in doing so (see below). Each interview was conducted in a location determined by the subject in an attempt to minimise any hesitation they might have about participating. Consequently, interview sites ranged from pubs, coffee shops, parks, shopping centres, to respondents' homes and the researchers' workplace (National Drug & Alcohol Research Centre). All respondents were guaranteed, both at the time of screening and interview, that any information they provided would be kept strictly confidential and anonymous. All interviews were conducted by one of the research team and took between 45 and 60 minutes to complete. 2.2 Structured Interview A structured interview was constructed that addressed the following areas: demographic characteristics, drug use history, heroin dependence, health, psychological functioning, heroin overdose, needle risk behaviours, criminal behaviours, the initiation of methadone injecting, methadone injecting procedures and the most recent methadone injection episode. The questionnaire was pilot tested on 10 heroin users, and refinements were made on the basis of this. The areas covered by the interview are outlined in detail below. 2.2.1 Demographic characteristics The demographic details obtained included: the respondent's gender, age, suburb of residence, level of high school and tertiary education, employment status, current form of drug treatment and prison record. 2.2.2 Drug use history In order to gain an indication of overall drug use, respondents were asked which drug classes they had ever used, which ones had they ever injected, and which ones had
3
they injected in the last 6 months. An estimation of how many days they had used each of the drug classes during the 6 months preceding interview was also sought. Further questions were asked about the first drug ever injected and how old they were when they first injected heroin. 2.2.3 Heroin dependence Current dependence on heroin was measured using the Severity of Dependence Scale (SDS)13. This is a 5-item scale, with scores ranging from 0-15. Higher scores are indicative of a higher degree of dependence. 2.2.4 Health The Health Scale of the Opiate treatment Index (OTI)14 was used to gain some indication of the respondent's current state of health. This scale is divided into items addressing signs and symptoms in each of the major organ systems, with one section specifically focusing on injection-related health problems. The higher the score obtained, the poorer the overall health of the subject. Respondents who had injected methadone were also asked about specific health problems related to the injection of methadone, and whether they had consulted medical practitioners about these problems. 2.2.5 Psychological functioning Psychological adjustment was assessed using the 28 item version of the GHQ15. This scale gives a global measure of non-psychotic psychopathology and is made up of the following 4 sub-scales: Somatic symptoms, Anxiety, Social dysfunction and Depression. Global scores range from 0-28, with 4/5 being the most commonly used cut-off point in determining the number of `cases' of psychopathology in a sample. 2.2.6 Heroin overdose Respondents were asked how many times they had overdosed, how long since they had last overdosed and whether they had ever been administered naloxone. 2.2.7 Needle risk behaviours The HIV Risk-taking Behaviour Scale (HRBS), a component of the OTI was used in assessing injecting behaviours in the month preceding interview that placed respondents at risk of either contracting or transmitting blood borne viruses. 2.2.8 Criminal behaviours
4
Using the Criminality Scale of the OTI, a record was taken of any property crimes, drug dealing, fraud and violent crimes committed during the month preceding interview. Higher scores on the Criminality Scale denote greater criminal involvement. As in the OTI, respondents were also asked whether they were currently facing any charges. 2.2.9 Initiation of methadone injecting Respondents were asked when they had commenced injecting methadone, whether they were in methadone maintenance at the time, their reason for injecting methadone and the source of the methadone used for initial injection. The frequency of injecting of `street' and personal methadone, the use of physeptone, and the availability and cost of `street' methadone were also recorded. 2.2.10 Methadone injecting procedures Respondents were asked about the procedures they employed in injecting methadone syrup. Specifically, the average and maximum amounts of methadone injected, the use of vein infusion sets ("butterfly clips"), and the size of syringes used to inject methadone. "Butterfly clips" are the street name for vein infusion sets. A vein infusion set consists of a needle attached to a length of plastic tube, to which a syringe is attached. They may be occluded between injections to prevent blood loss through the inserted needle, and improve stability for the use of larger sized syringes. 2.2.11 Most recent methadone injection episode Respondents were asked about the details of their most recent injection of methadone. Specifically, questions included time since last methadone injection, treatment status, amount injected, ratio of water to methadone, source of methadone, size of syringe, number of injections, and the use of infusion sets. 2.3 Analyses For continuous variables t-tests were employed. Categorical variables were analysed using chi2, and corresponding odds ratios (O.R.) and 95% confidence intervals (C.I.) were calculated. Where distributions were highly skewed, medians were reported. Highly skewed continuous data were analysed using the Mann-Whitney U statistic, a non-parametric analogue of the t-test. In order to determine which factors were independently associated with the injection of methadone, multiple logistic regressions were conducted. Backwards elimination of variables was used to select the most appropriate models. In analyses where "current users" of methadone were compared to other respondents, current use was defined as use within the six months preceding interview. All analyses were conducted using SYSTAT16.
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3.0 RESULTS 3.1 Sample Characteristics The sample consisted of 312 respondents, recruited from all areas of Sydney (Table 1). Males constituted 61% of the sample. The mean age of respondents was 28.8 years (SD 6.9, range 16-48), with males being significantly older than females (29.8 yrs v 27.3 yrs, t310=3.1, p
