Methadone patients four times more likely to overdose in month following treatment ending, study finds
Methadone patients are four times more likely to overdose in the month after their treatment ends, according to a new study.
They are also three times more likely to do so in the first month of treatment than at any other stage of treatment.
People with opioid dependence have a 10 times greater risk of premature death than the general population. The most effective treatment is the prescription of legal, substitution drugs, most commonly methadone.
A new study, led by researchers from the Royal College of Surgeons in Ireland (RSCI), analysed 2,899 people who were prescribed and dispensed methadone in addiction services between January 2010 and December 2015. They observed 154 deaths. Some 55 of these — 35.7% — were drug-related poisonings.
The rate of drug-related poisoning deaths was more than four times higher in the month after the ending of treatment, and it was more than three times higher in the first month of treatment than at any other stage of treatment.
These findings are consistent with growing evidence from other international studies.
Researchers did not observe any increase in deaths when patients were transferring between services, indicating that current structures are functioning properly. “Identifying a higher risk at the beginning, and immediately after the end, of treatment highlights that retaining patients in treatment for longer periods will save lives. People often cycle in and out of treatment, thereby increasing their exposure to repeated periods of high risk,” said Dr Gráinne Cousins, senior lecturer at RCSI’s School of Pharmacy and Biomolecular Sciences and the study’s lead author.
“Increasing patient awareness of the risk of overdose, and increasing the availability of take-home naloxone, may mitigate the risk of overdose during the high-risk periods, particularly following treatment cessation,” Dr Cousins said.
No deaths were observed in the first month after transfer between treatment providers.
The provision of opioid substitution treatment is also available in Irish prisons; if a prisoner is in treatment prior to incarceration, their treatment is continued in prison.
“Any inferences regarding risk must be cautious, as less than half our sample experienced a transfer, and among those who did, it was most frequently a transition to and from prison,” said Louise Duran, an RCSI postdoctoral research fellow in the School of Pharmacy and Biomolecular Sciences.
The study, published in the current edition of Addiction, was funded by the Health Research Board and was a collaboration between the School of Pharmacy and Biomolecular Sciences in RCSI, HRB Centre for Primary Care Research in RCSI, the HSE Addiction Services, Trinity College Dublin, and the HSE National Social Inclusion Office.
