Methamphetamine use was associated with poorer retention in opioid medication treatment across eight studies summarized in a 2023 scoping review. That consistent direction deserves attention, but it does not establish that methamphetamine alone caused a person to leave care or that opioid medication was ineffective.
What evidence did the review include?
Russell and colleagues searched through May 2023 for studies comparing opioid-medication patients with and without methamphetamine use. Eight studies qualified. Six involved methadone, one buprenorphine and one a broader national medication-treatment dataset. The settings included Canada, the United States, China and Iran. The latest underlying data were collected in 2018, making this historical evidence rather than a measurement of present-day retention.
The evidence was observational. Methamphetamine exposure was generally self-reported over differing time windows; one study used rapid urine testing. The review deliberately excluded studies that reported only undifferentiated “amphetamines” without methamphetamine-specific results. It did not conduct a pooled meta-analysis because the treatments and retention definitions were heterogeneous.
What did “discontinuation” actually mean?
It could mean no active buprenorphine prescription or program contact for more than 30 days, no longer reporting methadone at a later interview, or a recorded treatment discharge. In the national discharge dataset, reasons included completion, dropout, facility termination, transfer, incarceration and other reasons.
Those events are not clinically interchangeable. A transfer may preserve access to medication elsewhere; an administrative discharge may reflect a program rule. A retention statistic therefore needs its operational definition before it can be used to describe a particular patient’s course.
How large were the associations?
As summarized in the review, a Washington buprenorphine study of 799 people found an adjusted hazard ratio of 2.39 for discharge among those reporting past-month methamphetamine use, with a 95% confidence interval of 1.94–2.93. Its outcome incorporated the prescription/contact definition above.
A separate Vancouver methadone study reported an adjusted hazard ratio of 1.38, 95% confidence interval 1.03–1.85, for the higher-frequency methamphetamine category. The national treatment-discharge analysis reported an odds ratio of 0.48, 95% confidence interval 0.45–0.51, for six-month retention. These are estimates from different studies, with different adjustments and endpoints. Odds ratios and hazard ratios should not be averaged casually or translated into a universal percentage chance of dropout.
Why does a frequency gradient not settle causation?
Several studies found greater discontinuation with more frequent reported methamphetamine use. That pattern strengthens the reason to study the association, but frequency can also track housing instability, illness severity, other drug use, financial pressure and difficulty reaching services. Statistical adjustment cannot remove every unmeasured difference.
Service design may also contribute. The review discusses variation in medication access and programming between jurisdictions. A result about retention combines patients’ circumstances with what a treatment system requires and offers. It is not simply a laboratory experiment on a drug’s pharmacological effect.
How can these findings be used responsibly?
The evidence identifies a population that may face additional barriers to staying connected with care. It does not show that stopping opioid medication improves outcomes for people who use methamphetamine, and no such inference follows from these comparisons. Nor does a positive urine result demonstrate unwillingness to engage, a diagnosis of concurrent methamphetamine use disorder or impairment during a visit.
For an individual record review, distinguish the measured use period, medication, contact history, reason for discharge and availability of alternative care. The review supplies a research association, not a causal explanation for every interruption.
Source
Russell C et al. The impact of methamphetamine use on medications for opioid use disorder (MOUD) treatment retention: a scoping review. Addiction Science & Clinical Practice. 2023;18:48. doi:10.1186/s13722-023-00402-0. Review of historical observational human evidence.
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