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September 2, 2014

Making the case for methadone

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There are significant risks associated with opiate detoxification, notably relapse and increased risk of overdose

Dr Garrett McGovern writes that there are far superior outcomes for heroin users treated with opioid agonists compared to detoxification

Much has been written in the media recently, particularly in the UK, but also in IMT, regarding the role of long-term methadone treatment for heroin addiction. It has been proposed by both academics and politicians that methadone treatment should be time-limited.

Prof Neil McKeganey, Director of the Centre for Drug Misuse Research at Glasgow University, has been vitriolic in his criticism of methadone and believes that the drug should be used for no longer than two years. He would appear to have the backing of the British government. Prime Minister David Cameron stated recently that he does not endorse methadone as a long-term treatment, claiming “it does not deal with the problem” of drug misuse.

The idea of ‘stopwatch’ methadone treatment so enraged many specialists working in the field of substance misuse that a group of over 40 international experts wrote a letter in the Scotsman newspaper in April this year, extolling the virtues of methadone maintenance treatment and condemning the idea that methadone treatment programmes should be curtailed, with the focus on abstinence rather than harm reduction.

So, who is right? Let us examine the evidence.

Abstinence v harm reduction
In the early 1990s, there was an explosion of problematic heroin use in Dublin’s inner city that was rapidly spreading to the suburbs. With drug-related crime skyrocketing and the spectre of an HIV epidemic looming, the Government relented to pressure from public health experts and recognised the role of methadone treatment in reducing the harm caused by heroin addiction.

In 1998, the Methadone Treatment Protocol was devised and many GPs became involved in treating drug users. This approach of ‘harm reduction’ was criticised by those with an abstinence bent, who viewed methadone as a substitute for heroin and not an end in itself.

The ‘harm reduction’ camp pointed to the benefits of methadone in terms of reduced crime, reduced heroin use and overdose risk, reduced transmission of blood-borne viruses such as HIV and viral hepatitis, and improved mental and physical health. Unfortunately, this battle continues to rage, with opinions polarised.

Robust evidence base
The use of methadone for heroin dependence was pioneered by Drs Vincent Dole and Marie Nyswander in the mid-1960s in response to an explosion of problematic heroin use in New York City.

They hypothesised that heroin addiction resulted in permanent changes in brain chemistry, viewed opiate dependence as a metabolic disease and found that methadone ‘normalised’ addicts by reducing withdrawal symptoms and craving. They saw methadone as correcting, not curing, heroin addiction.

In the 45 years that have since passed, there has been extensive and consistent research evidence demonstrating the effectiveness of methadone treatment. Recent meta-analyses are strongly supportive of the role of methadone for the treatment of opioid dependence. These studies have demonstrated throughout the world that methadone can be effective in improving treatment retention, criminal activity rates and heroin use (NIDA 2010, Mattick, Breen, Kimber et al, 2003; Marsch 1998).

An overview of five meta-analyses and systematic reviews, summarising results from 52 studies and more than 12,000 opioid-dependent participants, compared methadone maintenance treatment (MMT) with a range of other treatments, including detoxification. The review concluded that methadone maintenance treatment was more effective than any other treatment, including detoxification (NIDA 2010, Amato, Davoli, Perruci et al, 2005). A systematic review consisting of 28 studies and 7,900 patients showed significant reductions in behaviours relating to HIV transmission for patients on methadone maintenance treatment (NIDA 2010; Gowing, Farrell, Bornemann et al, 2004).

In 1991, a randomised clinical trial was conducted in Bangkok, Thailand. The sample contained 240 heroin-dependent patients, every one of whom had previously undergone at least six detoxification episodes. The patients were randomly assigned to methadone maintenance versus 45-day methadone detoxification. The results showed that the patients in the methadone maintenance arm were more likely to complete 45 days of treatment, less likely to have used heroin during treatment and less likely to have used heroin on the 45th day of treatment (NIDA 2010, Vanichseni, Wonqsuwan, Choopanya et al, 1991).

A study carried out by researchers in 2000 compared ongoing methadone maintenance with six months of methadone maintenance followed by detoxification. The results demonstrated that methadone maintenance resulted in greater treatment retention (median, 438.5 vs 174.0 days) and lower heroin-use rates than did detoxification (NIDA 2010, Sees, Delucchi, Masson et al, 2000).

There is also good evidence supporting the use of the partial opioid agonist buprenorphine, a drug used for many years in other countries throughout the world but which, for a variety of reasons, is not widely available in Ireland.

In summary, opioid agonist treatment substantially reduces deaths, crime, HIV infection and drug use, while also assisting social functioning such as improved education, training, parenting and employment. Every £1 spent on methadone treatment saves between £4 and £7. Methadone treatment has been endorsed by three UN agencies: the United Nations Office on Drugs and Crime, the World Health Organization and UNAIDS. Methadone has been placed on the ‘essential medicines’ list by the WHO.

Methadone, like many other medications, does not work for every patient, every time; has side-effects that vary between patients; and is potentially lethal if taken by someone who is opioid naive.

Detoxification – poor outcomes
There are significant risks associated with opiate detoxification, notably relapse and an increased risk of overdose due to a loss of opioid tolerance. The risk is particularly high in injectors. To put this in an Irish perspective, a study published earlier this year in the Irish Medical Journal (Smyth BP et al) showed that 91 per cent of a sample of 109 patients who entered a residential rehabilitation programme reported a relapse, with 80 per cent of the relapses occurring within a month of discharge.

Five patients died and of the original group of 160 who entered rehab, 35 could not be followed up. These statistics are reflective of the international evidence and are a stark reminder of the dangers of detoxification. This does not mean that detoxification is contraindicated, but patients who embark on the process should be warned of the risks and should never be forced to come off agonist drugs such as methadone and buprenorphine.

Addiction is a disease with biological, psychological and social roots and there are numerous stressors that can lead to relapse. Each case is different and management needs to be individualised. The proposal to time-limit methadone treatment is ludicrous, unethical, dangerous and operates on the premise of ‘one size fits all’.

Throughout the country, there is a developing heroin problem that is reaching epidemic proportions. Unfortunately, the response to this problem has been abysmally slow. If reports are to be believed, the Government plans to address the issue by setting up a number of inpatient detoxification units.

This, in my opinion, is a disastrous idea and likely to worsen the problem rather than improve it. In these harsh economic times, resources should be directed at evidence based, value-for-money interventions, not expensive options that are likely to cost lives as well as money.

‘What would be the likely outcome if a doctor, against the patient’s wishes, discontinued a medication from which the patient clearly derived benefit and the withdrawal of that treatment resulted in harm?’

Chronic relapsing condition
Doctors working in the field of addiction, particularly opiate addiction, are often criticised for ‘parking’ patients on methadone and failing to encourage them to come off the drug. Whilst I take umbrage with the semantics of this allegation, there is more than an essence of truth in it.

My response is simple. Why would any doctor insist that a patient stops taking a drug that is of immeasurable benefit to his/her health and that the likely consequences of denying the patient the drug is a deterioration in the patient’s condition and possibly death? Compare this with other chronic relapsing conditions such as diabetes, rheumatoid arthritis or epilepsy.

What would be the likely outcome if a doctor, against the patient’s wishes, discontinued a medication from which the patient clearly derived benefit and the withdrawal of that treatment resulted in harm? It is fair to say that either the patient or their family would take a grievance against the doctor, by way of legal action or a complaint to the Medical Council. Why is the treatment of heroin addiction not measured by the same standards?

The answer probably lies in the fact that heroin users are stigmatised, often seen as deviant miscreants whose misery is self-inflicted. If that is the case, then why is the same charge not levelled at lung cancer patients or patients with ischaemic heart disease? Actually, the list of ‘self-inflicted’ diseases extends far beyond these few examples.

Punitive practices
This discussion would not be complete without reference to another form of detoxification, that is reducing from methadone for providing ‘dirty urines’. In 1998 (and some time before), when the methadone treatment protocol was implemented, it was commonplace to exclude patients from treatment on the basis of providing opiate-positive urine screens.

The belief was that methadone treatment with continued heroin use increased the risk of overdose death and that it was wise to reduce the dose of methadone to decrease this risk.

This flies in the face of the research evidence which clearly states that patients should never be excluded from treatment on the basis of urine results (well recognised to be a poor measure of both drug use and stability) and that doing so significantly increases the risk of accidental overdose and other harms such as HIV and hepatitis C transmission and other consequences of injecting behaviour, such as deep vein thrombosis and cellulitis.

Thankfully, practitioners are today more aware of the research than they were in 1998, although there are still areas of the country where this practice is occurring. This is increasing patient harm and should not be happening.

Conclusion
Opioid agonist treatment is the strongest evidence-based intervention in the treatment of opioid dependence, with decades of research demonstrating its effectiveness in reducing heroin use, crime, the transmission risk of blood-borne viruses and improving mental physical and social health. Detoxification, however, is associated with a high rate of relapse and mortality.

Nevertheless, detoxification is socially and politically popular and there is a campaign (particularly in the UK) to upgrade detoxification and limit the coverage of opioid agonist treatment. This is foolhardy and will result in more deaths, more crime, more drug use and significantly more cost to the taxpayer.

Patients should never be forced to come off methadone (or buprenorphine). They, and only they, should make the choice: they should be warned of the risks of detoxification and they should be fully supported by their treatment providers, even if against medical advice, as the risk of harm will likely be greater without medical support.

References on request

  • Dr Garrett McGovern,

GP Specialising in Substance Abuse,
Sandyford, Dublin 18.