NALTREXONE'S GOOD FOR THE RIGHT PEOPLE

The current furore over naltrexone treatment of heroin dependence is
unlike anything I have experienced in 25 years of working in the drug
and alcohol field.

Understandably, everyone is seeking answers to the problems of heroin
addicts. The emphasis in Australia in recent years has been on
pharmacological treatments, especially methadone maintenance. Overall,
the risk of death, overdose and major disease is reduced by 75 per
cent with methadone.

Naltrexone is, in principle, a good treatment. In most people, it
blocks the effect of injected heroin and suppresses craving but it is
only as good as the motivation of users. Patients on naltrexone
tablets have to renew their commitment to keep off heroin every time
they take the tablet. Unlike methadone, naltrexone has no opiate-like
properties and does not cause even mildly pleasant effects. Without
the soothing effect of opiates, some people find life hard. With
naltrexone, there is a constant need for support and advice. Given and
used carefully, it can produce brilliant results.

One must recognise that injecting heroin is a dangerous activity.
Between one and three percent of regular users die each year.
Aggregating the experience of several groups across the country, there
is clearly an excessive number of heroin overdoses among people
treated with naltrexone, compared with methadone. Indeed, naltrexone
treatment may be associated with a mortality rate similar to or even
higher than that seen in untreated heroin users. Overdoses occur when
treatment stops, often about the third day after the last naltrexone
is taken. When people use heroin regularly, tolerance to its effects
builds up. This actually protects from overdose, to some degree.

When patients start on naltrexone, the unique properties of the drug
afford considerable protection from heroin's effects. However, at the
same time the tolerance that has built up is diminished.

If the person ceases to take naltrexone, they will be as susceptible
to the effects of heroin as they were the first time they used it.
Given that they will be likely to use a dose similar to what they took
during their years of regular use, they will, in effect, be taking a
massive overdose.

This risk of overdose is inherent in treatment with naltrexone. The
claims of some commercial providers of rapid detoxification and
naltrexone have been as misleading and irresponsible as I have seen in
my medical career. Treatment with naltrexone requires effort by the
user, his or her partner, parents, friends and crucially, by the
doctor and clinical staff. Treatment with naltrexone in the tablet
form clearly has its limitations -- the need for an almost obsessional
persistence with treatment being the major one. A naltrexone implant,
inserted into the fat underneath the skin via a small incision, allows
for slow absorption and usually lasts about two months.

When a person has a repeated pattern of heroin use and has developed a
dependence, I would normally advise methadone maintenance as the most
beneficial treatment.

In my view between 5 and 10 per cent of heroin dependent persons are
likely to accept and benefit from naltrexone treatment. We need to
better identify those who will respond especially well to naltrexone
and this is one of the aims of a recent trial at the Royal Brisbane
Hospital. Naltrexone is suitable for those who are highly committed to
abstinence and have a strongly supportive network of family and friends.

We need to progress our research into the treatment of heroin
dependence, including controlled trials of naltrexone implants; and
the development of vaccines against opiates, which are becoming a
practical reality. I am strongly committed to testing new treatments
against the best of what we can currently provide.