September 2015 |
drinkanddrugsnews
| 7
Is it time for us to reappraise our relationship
with the life-saving drug methadone?
Dave Marteau
discusses the evidence
Read the full version online at:
S
ince the early 1970s, methadone has been the predominant opioid
prescribed in the UK for the ongoing treatment of heroin addiction. It
has proved extremely useful in the fight to contain HIV among injecting
heroin users, and there is strong evidence that longer-termmethadone
treatment of heroin addiction reduces death rates by as much as 50 per
cent. Moral objections have been voiced by many about a treatment that swaps
addiction to one drug (heroin) for dependence on another (methadone), but
perhaps we can all agree on the primacy of life itself: it trumps any argument.
In 2007 the then-National Institute for Health and Clinical Excellence (NICE)
positively evaluated methadone and buprenorphine. In circumstances where
assessments had suggested that both drugs were equally suitable, NICE
recommended that ‘methadone should be prescribed as the first choice’.
However, in a review of drug-related deaths in France between 1994 and
1998, Marc Auriacombe found that, set within the context of numbers of
prescriptions issued, methadone was at least three times more lethal than
buprenorphine in respect of overdose deaths within the French population as a
whole (
ie
, among patients and the wider public).
On the subject of the relative toxicity of methadone and buprenorphine, NICE
had this to say:
‘Comparison of data from population cross-sectional studies suggests that the
level of mortality with BMT [buprenorphine maintenance] may be lower than
that with MMT [methadone maintenance], although other authors have
commented that these data were unlikely to capture all related deaths.’
This was a cursory summary of an important matter in 2007; it would be
insufficient to the point of negligence now. In 2009 James Bell and colleagues in
New South Wales found that, per prescription, methadone was 4.25 times more
lethal than buprenorphine. This year Rebecca McDonald, Kamlesh Patel and I
carried out a similar but larger study in England and Wales. We found that
between 2007 and 2012, 57 death certificates mentioned buprenorphine, while
2,366 death certificates mentioned methadone.
Allowing for a calculation that seven methadone prescriptions were issued for
every buprenorphine prescription, methadone emerged as six times more
dangerous across the population as a whole. The picture in Scotland appears no
prettier. Between 2011 and 2013, heroin and its metabolite morphine were
implicated in 538 drug poisoning deaths; methadone was found to be implicated
in 663 deaths.
So how is it that a drug with the potential to halve a patient’s risk of dying
ends up killing so many people? The answer is horribly simple: while most
patients are safer on methadone, the wider population are at continued risk from
diverted supplies of the drug. The National Programme on Substance Abuse
Deaths found that of 1,117 UK deaths that involved methadone alone or in
combination with other drugs, only 36 per cent occurred among individuals who
were known to be receiving methadone treatment.
To be fair to NICE, their methodology was designed to determine the cost-
effectiveness of a drug, not its safety. That same methodology, based solidly on
randomised controlled trials, compares the outcomes for a patient group on drug
A with those for members of a patient group on drug B. No persons outside of
these two groups are considered. This is a very good means to evaluate
antibiotics or chemotherapy, but altogether less suitable for drugs intended to
treat people with a drug-taking problem. No one on antibiotic ‘A’ would be likely,
for instance, to consider trading their medication with a non-patient, or to be put
under duress to hand over their medication outside the pharmacy.
There is another stark statistic: of all drugs detected at post-mortem over the
past three years in Scotland, methadone has, at 93 per cent, the highest degree
of implication in the unfortunate person’s death. So, if you were to die from a
drugs overdose, and methadone was among the substances found in your body,
there is a 93 per cent chance that it had been wholly or partly responsible for
your death. This makes methadone significantly more toxic than heroin, (which
had an implication rate of 83 per cent), buprenorphine (65 per cent) and cocaine
(63 per cent). Put simply, methadone is the most dangerous drug out there.
Methadone has the capacity to retain more people in treatment than
buprenorphine, but the evidence is now overwhelming that it is significantly
more lethal. Hundreds of our fellow UK citizens are dying every year from
methadone poisoning. If we agree with the premise at the start of this article
that the value of life prevails over any other argument, then we have now to
relegate methadone to a secondary option for the substitute treatment of opioid
dependence, behind buprenorphine and buprenorphine-naloxone. Failure to
change would indicate that we are less courageous than our clients in
confronting a dangerous pattern of our own behaviour.
For the record, I have never taken nor will ever take a penny from a drug
company.
Full references accompany this article at
Dave Marteau is research fellow at the University of London
‘How is it that a drug
with the potential to halve a
patient’s risk of dying ends
up killing so many people?
The answer is horribly
simple: while most patients
are safer on methadone,
the wider population are at
continued risk from diverted
supplies of the drug.’
