For some a magic bullet, for others, an unsafe experiment with human beings as the guinea pigs, naltrexone implants and injections block the effects of heroin for weeks or months. Naltrexone is an opiate antagonist which in itself has no psychoactive effects, but commandeers the neural receptors targeted by opiate-type (‘opioid’) drugs. The implant form inserted under the skin blocks opiates usually for two to six months; an intramuscular depot injection approved for medical use in the USA and Russia lasts about a month. Both avoid the need to take medication daily, in theory overcoming the main shortcoming of oral naltrexone – that patients usually stop taking the tablets and resume heroin use.

We’ll see that while no instant solution, these preparations represent a valuable extension to the range of interventions suitable sometimes for some people depending on their characteristics and circumstances – in particular, those ready for abstinence from opioid drugs. As with other approaches, the social and psychological adjustments needed to stabilise a non-addicted life are likely to take time and require help which goes beyond medication, though this can help create the space for such adjustments.

This hot topic concerns long-acting forms of naltrexone only and their use among usual treatment populations. Another hot topic has narrowed in on the highly controversial practice of coercing or forcing opiate-dependent offenders to enter naltrexone treatment.