Effectiveness of Opiate Substitution Treatment in Treatment of Opioid Dependence

Written by Georgia Henderson


Opioid dependence is a chronic relapsing disorder that affects millions of people worldwide. Its signs and symptoms reflect compulsive, prolonged self-administration of opioids, which typically results in a tolerance where abrupt discontinuation of the substance will cause a withdrawal. 

It was estimated in 2012 that a minimum of 0.3% of New Zealanders aged 15-64 years were dependent on opioids and this number is thought to be increasing.

Opiate Substitution Treatment (OST) is the primary treatment used in opiate dependencies, however due to the underlying complexities that surround its users assessing, its effectiveness and what factors affect this are essential. 

Various factors are identified that affect success in OST which can be divided into pre-treatment factors such as stigma and long wait times for treatment; treatment factors such as the medications themselves, side effects and the level of psychosocial support; and maintenance/compliance factors that may lead to relapse which are accessibility to treatment and dependence on the substitute drug as well as comorbid psychiatric or substance abuse issues. 


Opioid dependence is characterised as a chronic relapsing disorder that affects millions of people worldwide. Its signs and symptoms reflect compulsive, prolonged self-administration of opioids, natural, synthetic or semi-synthetic, which typically results in a tolerance where abrupt discontinuation of the substance will cause a withdrawal (Cacciola, Severt, Ruetsch & Tkacz, 2012). 

It was estimated in 2012 that a minimum of 0.3% of New Zealanders aged 15-64 years were dependent on opioids and this number is thought to be increasing. The 2014 Global Drug Survey was conducted and results found that 8.7% of the respondent population had used opioid analgesics in the previous year, however in New Zealand this number was significantly higher at 19.1% second only to the USA (“Identifying and managing addiction to opioids”, 2014).

Exposure through clinical placement at community alcohol and drug service highlighted opioid dependence as one of the most complex forms of addiction. There were various causes for these opioid dependencies and all clients appeared to have underlying personal issues that needed to be addressed alongside their dependency issues.

Opiate substitution treatment (OST) has been the primary treatment for opiate dependence in New Zealand for the past 40 years (Adamson, Deering & Sellman, 2014). People on OST receive a daily dose of the substitute drug, which is a long acting opioid that allows the patient to step away from the reinforcing effects of the shorter acting opioids (“Identifying and managing addiction to opioids”, 2014). Up until 2012 Methadone maintenance treatment was the dominant form of OST, however the introduction of Buprenorphine/Naloxone (Suboxone) has been seen as a new era in treatment with its view orientated towards broader recovery and wellbeing for its users (Cacciola et al., 2012).

Investigating the effectiveness of OST in treating opioid dependence is important, as this form of treatment has remained undermined by stigma and risk concerns due to its association with methadone and it has struggled to be accessible to illicit drug users in the past.

I have used the PECOT model to refine my research question and the purpose of my investigation is to determine whether “In people with opiate dependence is opioid substitution treatment (OST) effective in reduction or cessation of illicit opiate use”. From here I aim to establish what the main factors are that may influence its effectiveness and what recommendations I can make that may be improved on.

OST is a treatment form used all over the world so there are various sources of information and statistics from these countries. However, study information and statistics of OST in New Zealand is limited.The key findings of this review have been that OST is effective in treating opioid dependency, however it is not as effective alone. Various sources have cited that in order for OST to be most effective it must be used in conjunction with psychosocial support. A range of factors have been found to influence the effectiveness of treatment, these being; Pre-treatment factors such as stigma both socially, personally and institutionally and the long wait-lists and wait times for treatment; Treatment factors such as the medications themselves and their side effects and the amount of psychosocial support integrated into treatment; and maintenance/compliance factors which may lead to relapse, these include accessibility of treatment and dependence on the substitute drug as well as co-morbid psychiatric or substance abuse issues (Adamson, et al., 2014; Cacciola et al., 2012; De Maeyer, Naert, Vanderplasschen & Vander Laenen, 2015).

  Pre-treatment Factors

Since OST was pioneered in the 1960s its preceding trials and outcome studies have confirmed its effectiveness in improving the general health and functioning of its clients as well as reducing injection opioid use, mortality and criminal offending (Adamson, et al., 2014). In spite of its proven success, issues still remain regarding the perceptions of treatment and the stigma associated with methadone use and drug addiction, which have prevented people from engaging in or accessing services in the first place (Adamson, et al., 2014). As cited in Adamson, et al. (2014) five perspectives have influenced trends and tensions of OST in New Zealand. The abstinence model whose perspective of OST was “methadone treatment is like giving gin to an alcoholic” was a more moralistic approach, which impacted the dose and duration of treatment, often prescribing low/sub-therapeutic doses for shorter periods of time (Adamson, et al., 2014). This perspective directly conflicts to Dole & Nyswander’s model, where opioid dependence is described as a chronic medical condition, where treatment is viewed as life-long as long as the clients are benefitting, reflecting the use of insulin for diabetics. This model drove clinicians to become more narrowly focused on substance use rather than the broader health and functioning of the patient (Adamson, et al., 2014). The protocolised approach provided negative sanctions for illicit substance use such as reduced takeaway doses and involuntary discharge if urine screens were found to be “dirty” impacting negatively on its patients’ responses to treatment, rather than giving them positive reinforcement for change.

These moralist and medicalised approaches were later challenged by the appearance of the HIV/AIDS epidemic of the 80s directing treatment to be focused on the more current approach of harm reduction, the aim being to recruit and retain injecting opioid users in OST treatment. From here admission and dosing became more flexible and bringing forward the reality of other substance use and relapse, which also lead to introduction of needle exchanges (Adamson, et al., 2014). Treatment has become a more comprehensive and individualised approach concurrent with the medical treatment of other relapsing disorders. The need to incorporate the impact of co-occurring psychiatric conditions on treatment was recognised and serum methadone concentration technology was developed, both providing accuracy and a more comprehensive approach to treatment (Adamson, et al., 2014).

“Harm reduction is characterised by a humanistic, non-judgemental approach with respect for the autonomy of drug users and their rights for qualitative health care” (De Maeyer et al., 2015, p272) and OST is central to this approach. The De Maeyer et al. (2015) reports barriers of social control and stigma as well as institutional stigmatisation of methadone clients as “undeserving customers”, which disqualifies these individuals from full social acceptance and the potential to discredit recovery instead of development of positive identities.  This stigmatisation and discrimination directly contrasts with the ideals of harm reduction despite the shift in focus from the moralistic perspective and various reports have cited unwillingness of general practitioners and pharmacists to provide OST.

Lengthy waiting times and waiting-lists have been identified as barriers to illicit opioid users accessing treatment in both Adamson, et al. (2014) and De Maeyer et al. (2015) In 1995 it was estimated that as high as 20,000 people in New Zealand were using opiates regularly but only 2500 were receiving methadone treatment. This was the first time the gap between treatment need and provision was reflected by the presence of waiting lists. A 2001 Ministry of Health report found that most methadone treatment programmes in the South Island had waiting list of around nine months, but this was considered an underestimation as opioid dependent people were deterred from presenting for treatment (Adamson, et al., 2014).

Interim prescribing by authorised GPs was made a protocol for people with established opioid dependence where they would receive low doses of methadone if waiting times were over two weeks, however effective this was it was not enacted by all regions and waitlists remained longer then the recommended two weeks. Current waiting times for admission to treatment vary from 2-290 days, with a median 30 days (Adamson, et al., 2014).

The lengthy waits are a major barrier for effectiveness of OST as the Opioid Substitution Treatment Practice Guidelines state that OST will be significantly more successful when services are accessible, including prompt entry (Ministry of Health, 2014, ).

  Treatment Factors

The medications and how they work are fundamental to OST treatment. There is significant evidence that Methadone and Suboxone are both effective in bringing stability to the lives of opiate dependent people and improving health as well as reducing drug-related re-offending, criminal behaviour, injecting and sharing behaviour, HIV infection rates and mortality (Best, Bordon, Conroy & Tanner, 2011). The decision on which drug to use is based on an individual case factors, client preferences and is related to the estimated risks (Best et al., 2011).

Medication side effects may deter some clients, the most commonly experienced being feeling tired and sweating heavily (De Maeyer et al. 2015).   Methadone’s most common side effect include nausea, vomiting, constipation, drowsiness and confusion (BNM Group, 2014). Suboxone’s most common side effects include headache, pain, nausea, stomach pain, constipation and sleep problems (Cacciola et al., 2012). Clients have consistently reported more clarity of thinking when on Suboxone compared with methadone, however this is not always seen as a positive effect as it requires a greater level of psychosocial therapeutic support then on methadone (Best et al., 2011).

Additional psychosocial support is essential in enhancing effective OST; forms of support may be simple such as the provision of food or shelter or complex such as structured psychotherapy (De Maeyer et al., 2015). Generally, respondents from the De Maeyer et al. (2015) study were satisfied with services, however despite the evidence of the part psychosocial support plays in enhancing OST effectiveness, 4/10 clients did not receive any support in the three months prior to the interview, despite a large number stating that they would have liked to receive some form of support. Only 28% of respondents received weekly support, while for 44% the frequency was monthly or less. Besides emotional support, links to ancillary services was stressed along with increased flexibility of support services that are normally limited to weekdays and business hours (De Maeyer et al., 2015).

One third of respondents mentioned needing occupying, in order to deal with the emptiness of everyday life that was once filled with the drug use (De Maeyer et al. 2015). Also mentioned was the need for somewhere to “hang around” to feel safe and to spend the day (De Maeyer et al. 2015). Recreational support and somewhere for them to go that was safe for them would both be beneficial to these clients, to decrease the likely hood of a relapse from boredom or exposures to environments that may trigger them (De Maeyer et al., 2015). 

Along with which medication is best suited to the individual, the dose is just as, if not more important to adequately treat their dependence. If the dose being received is too low and not meeting therapeutic levels, then the client may experience discomfort due to insufficient opioid effect. This may motivate them to use other drugs, which could have potentially fatal consequences. Because of this risk, providers need to tailor dose increases to each individual. The recommended therapeutic range for Methadone is 60-120mg and for Suboxone 12-24mg per day. Clients may be at either end of the dose range (Ministry of Health, 2014). While it is the physician’s decision on the dose prescribed, the clients input is integral to meeting their needs adequately and a lack of input could potentially make the patient feel permanently attached to their substitute drug (De Maeyer et al., 2015).

  Maintenance/Compliance Factors

Ideally the end goal for many OST clients would be to be totally free of opiate drugs and OST completely. Almost all participants in the De Maeyer et al. (2015) study expressed a desire to decrease their current dose and ultimately be no longer dependent on the substitute drug (De Maeyer et al., 2015). In many cases OST is described as “liquid handcuffs” which refers to the restrictions it has on daily life including gaining or maintaining employment (Adamson, et al., 2014).

The most negative effects of OST cited in De Maeyer et al. (2015) are indefinite duration of treatment and the “dependence” on the substitute drug. While Adamson, et al., (2014) states that a concern of its patients was the judgement and stigma of methadone treatment, negative staff attitudes and an overly restrictive and paternalistic approach, patients reported that OST provision lacked supervision with liberal prescriptions (De Maeyer et al., 2015).

“Dependence” on the substitute drug in OST extends beyond the physical dependence, it also extends to access to the treatment. Some of the most common patient identified barriers were the restricted takeaways, being tied to staying in one place with restricted travelling opportunities and having to go to a chemist every/most days (Adamson, et al., 2014).

OST medications are fully funded by PHARMAC in New Zealand (Ministry of Health, 2014), which means that OST clients do not have the daily financial burden like other countries, however the restrictive and/or inconvenient locations and operating hours of service providers have been seen as a barrier to find or hold down employment (Hser, Jiang, Li, Peng, Wu, Zhang & Zhao, 2013). If the purposes of OST is to restore normality and stability to the lives of its clients then the restrictions it places on employment is a major issue, which could potentially play negatively on the clients’ relationships with employers or force them to be continually without employment and a stable income.

Providing takeaway doses is one way that flexibility can be obtained in OST for stable clients, these are “any doses of opioid substitution treatment (OST0 medication that are not consumed under observation at a pharmacy, specialist service, primary care practice or any designated place where OST medication can be safely dispensed.” (Ministry of Health, 2014 p. 36). While takeaways do allow some flexibility there are some restrictions with clients generally being required to attend the pharmacy for at least three non-consecutive days a week until they are stable enough to be transferred to their primary care provider. The restrictions on takeaways mean that extraordinary circumstances like illness can be challenging and planned holidays need to be well considered and arrangements have to be made at out-of-area pharmacies willing to dispense (Ministry of Health, 2014).

The introduction of Suboxone allows its clients more freedom than with methadone. Suboxone was designed to minimize abuse and diversion while retaining the positive aspects of methadone. Unlike Methadone maintenance where daily or most daily dispensing is required, Suboxone is able to require only one pharmacy and physician visit per month once stable, however this requires clients to be responsible for administering their own dose daily, which causes variations in compliance (Cacciola et al., 2012).

The link between compliance to medication and the likelihood of relapse was made in Cacciola et al. (2012) with non-compliant patients being over 10 times more likely to relapse to opioid abuse then those who were compliant (Cacciola et al., 2012). Factors identified that drive this non-compliance include comorbid psychiatric or substance abuse disorders, psychosocial stability and the client’s adherence history with other medications (Cacciola et al., 2012).

Coexisting mental health problems have been observed in OST clients, the most common include personality, mood and anxiety disorders and polysubstance abuse. Post traumatic stress disorder affects at least one third of clients usually compounded by multiple traumatic experiences (Ministry of Health, 2014). Many of these mental health problems improves once clients are stabilised on OST however underlying problems often emerge as addictions resolve which highlights the need for primary and specialty service to implement chronic care management for these individuals (Ministry of Health, 2014).

Along with the co-existing issues in clients’ health, there are also various triggers that may cause them to relapse into opiate abuse. Stress, renewed contact with or availability of drugs, a past/family history of substance abuse, a high number of undesirable life events and a heavy burden to comply with the program in order to reduce the physiological and psychological triggers (Cacciola et al., 2012). It is the responsibility of service providers to develop contingency and joint crisis plans and negotiated safety plans with the client to manage these situations and triggers is they arise.

The MOH recommended goal is for a 50/50 share of OST provision between general practice and specialty services. While the receivers of OST have increased to over 5000, the provision of stable OST clients to primary care has only risen to 29%, which is short of the target (Adamson, et al., 2014). Ideally when a client has achieved a sustained period of stability, then the providers should facilitate a shift towards primary care. Shifting service provision to primary care frees up more intensive resources for the speciality services and facilitates opportunistic care and normalisation of treatment (Ministry of Health, 2014). Staffing issues and significant barriers still exist shifting clients into primary care, which include unavailability of GPs and unwillingness to provide OST, considered to in part be influenced by stigma, risk concerns and misperceptions associated with treatment and the treatment group, a lack of training and patients deemed not yet ready for treatment (Adamson, et al., 2014). These barriers are for the most part service related barriers which need to be addressed in order to improve service delivery and facilitate effective recovery for OST clients.


From this literature review I have established recommendations that I believe will improve on making OST more attractive and accessible for opiate drug users and increase retention and maintenance in treatment, which will hopefully lead to a greater number of clients moving through to primary care and increasing quality of life and wellbeing for these individuals. These recommendations are:

> Provide education to health professionals on OST and redirect the point of view to treatment in line with that of other chronic health conditions to reduce stigma and misperceptions of OST and its clients.

Stigma and misperceptions of OST and its clients, as well as unwillingness of GPs and pharmacists to Provide OST have been identified as major barriers to clients engaging with services and shifting from specialist services to primary care. By increasing knowledge of treatment and reducing the associated stigma clients may be more encouraged to engage with services to seek help for their addictions. Increasing the number of GPs and pharmacists willing to provide OST may facilitate the shift of more clients into primary care and out of specialist services, while also increasing normalisation of OST and flexibility in the lives of its clients.

> Engage clients in treatment sooner and reduce wait times.

OST has been shown to be more effective when services are accessible and entry is prompt, so getting clients into treatment sooner should increase the likelihood of retention and continued engagement with the service as well as increasing the number of clients in treatment.

> Increase the level of psychosocial support available to OST clients throughout all stages of treatment.

It has been proven by many sources that OST is much more effective when used in conjunction with psychosocial support. OST clients have expressed the desire for support, however a small fraction of these clients received it, so engaging clients in and providing psychosocial support at all levels of treatment should improve their success in OST and provide a more holistic approach to health.

> Engage OST clients in all stages of care and goals setting to increase person-centred care.

In past OST providers have been focused heavily on the medications and doses with little insight into clients’ goals or desired outcomes for treatment, however in order for clients to fully engage and stay committed to treatment they need to be motivated and they need to have a strong, trusting relationship with their care provider.

> Encourage OST staff to shift stable clients into primary care sooner, to allow normalisation of OST and greater flexibility.

Shifting clients to primary care for their OST provision is a further step in the ‘recovery’ of the client from their opiate dependence. This shift may provide some encouragement of achievements made by the clients in treatment, it provides more flexibility for daily life and it brings normality to prescribing of OST medications in conjunction with any other chronic condition.

In conclusion, this literature review has established that OST is effective in reduction and cessation of illicit opiate drug use, however it is most effective when not used alone but with various psychosocial supports. Many barriers were identified that could cause OST to become less effective, these included the pre-treatment factors in presence of long wait times to start treatment and the stigma associated with opiate drug taking and OST treatment; treatment factors such as the medication and side effects as well as the level of psychosocial support and finally maintenance/compliance factors of accessibility, dependence on the substitute drugs and co-existing issues or triggers. While there have been many barriers identified I believe that implementation of my recommendations could significantly improve the provision of OST and create a more supportive, effective environment to improve the quality of life and wellbeing of OST clients.


Adamson, S., Deering, D., & Sellman, J. D. (2014). Opioid substitution treatment in New Zealand: A 40 year perspective. The New Zealand Medical Journal (Online), 127(1397), 57-66. Retrieved from http://search.proquest.com.op.idm.oclc.org/docview/1543575582?accountid=39660

Best, D., Bordon, N., Conroy, S., & Tanner, G. R. (2011). Comparing methadone and Suboxone in applied treatment settings: the experiences of maintenance patients in Lanarkshire. Journal Of Substance Use, 16(3), 171-178 8p. doi:10.3109/14659891.2010.526480

BNM Group. (2014). Methadone Molteni [Data sheet]. Retrieved from http://www.medsafe.govt.nz/profs/datasheet/m/methadonemol tenisol.pdf

Cacciola, J., Severt, J., Ruetsch, C., & Tkacz, J. (2012). Compliance with Buprenorphine Medication-Assisted Treatment and Relapse to Opioid Use. American Journal On Addictions, 21(1), 55-62.

De Maeyer, J., Naert, J., Vanderplasschen, W., & Vander Laenen, F. (2015). Treatment satisfaction and quality of support in outpatient substitution treatment: opiate users’ experiences and perspectives. Drugs-Education Prevention and Policy, 22(3), 272–280.

Hser, Y.I., Jiang, H., Li, J., Peng, C.Y., Wu, F., Zhang, R., & Zhao, M. (2013). Methadone maintenance treatment in China: perceived challenges from the perspectives of service providers and patients. Journal of Public Health,35(2), 206-212. doi: 10.1093/pubmed/fds079

Identifying and managing addiction to opioids. (2014). Best Practice Journal, 64(1), 16 - 25.

Ministry of Health. (2014). New Zealand Practice Guidelines for Opioid Substitution Treatment. Wellington: Author.