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Washington State Institute for Public Policy
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Injectable naltrexone for opiates

Substance Use Disorders: Medication-assisted Treatment
Benefit-cost methods last updated December 2019.  Literature review updated December 2016.
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Long-acting injectable naltrexone is used as an alcohol or opiate antagonist to treat alcohol or opiate dependence. Naltrexone is an antagonist that blocks the euphoric effects of alcohol or opiates, and patients do not develop tolerance or experience withdrawal symptoms when they stop taking the drug. It is intended to reduce cravings and prevent relapse. Patients also receive counseling therapies such as cognitive behavioral treatment or motivational enhancement therapy. Injections are typically administered monthly for one to six months. Our benefit-cost estimates assume one full year of treatment and one corresponding full year of effectiveness.
For an overview of WSIPP's Benefit-Cost Model, please see this guide. The estimates shown are present value, life cycle benefits and costs. All dollars are expressed in the base year chosen for this analysis (2018). The chance the benefits exceed the costs are derived from a Monte Carlo risk analysis. The details on this, as well as the economic discount rates and other relevant parameters are described in our Technical Documentation.
Benefit-Cost Summary Statistics Per Participant
Benefits to:
Taxpayers $1,168 Benefits minus costs ($18,681)
Participants $1,432 Benefit to cost ratio ($0.07)
Others $596 Chance the program will produce
Indirect ($4,440) benefits greater than the costs 0 %
Total benefits ($1,244)
Net program cost ($17,437)
Benefits minus cost ($18,681)

Meta-analysis is a statistical method to combine the results from separate studies on a program, policy, or topic in order to estimate its effect on an outcome. WSIPP systematically evaluates all credible evaluations we can locate on each topic. The outcomes measured are the types of program impacts that were measured in the research literature (for example, crime or educational attainment). Treatment N represents the total number of individuals or units in the treatment group across the included studies.

An effect size (ES) is a standard metric that summarizes the degree to which a program or policy affects a measured outcome. If the effect size is positive, the outcome increases. If the effect size is negative, the outcome decreases. See Estimating Program Effects Using Effect Sizes for additional information.

Adjusted effect sizes are used to calculate the benefits from our benefit cost model. WSIPP may adjust effect sizes based on methodological characteristics of the study. For example, we may adjust effect sizes when a study has a weak research design or when the program developer is involved in the research. The magnitude of these adjustments varies depending on the topic area.

WSIPP may also adjust the second ES measurement. Research shows the magnitude of some effect sizes decrease over time. For those effect sizes, we estimate outcome-based adjustments which we apply between the first time ES is estimated and the second time ES is estimated. We also report the unadjusted effect size to show the effect sizes before any adjustments have been made. More details about these adjustments can be found in our Technical Documentation.

Meta-Analysis of Program Effects
Outcomes measured Treatment age No. of effect sizes Treatment N Adjusted effect sizes(ES) and standard errors(SE) used in the benefit - cost analysis Unadjusted effect size (random effects model)
First time ES is estimated Second time ES is estimated
ES SE Age ES SE Age ES p-value
38 1 153 -0.049 0.364 38 0.000 0.000 39 -0.049 0.893
38 5 337 -0.566 0.152 38 0.000 0.000 39 -0.566 0.001
1In addition to the outcomes measured in the meta-analysis table, WSIPP measures benefits and costs estimated from other outcomes associated with those reported in the evaluation literature. For example, empirical research demonstrates that high school graduation leads to reduced crime. These associated measures provide a more complete picture of the detailed costs and benefits of the program.

2“Others” includes benefits to people other than taxpayers and participants. Depending on the program, it could include reductions in crime victimization, the economic benefits from a more educated workforce, and the benefits from employer-paid health insurance.

3“Indirect benefits” includes estimates of the net changes in the value of a statistical life and net changes in the deadweight costs of taxation.
Detailed Monetary Benefit Estimates Per Participant
Affected outcome: Resulting benefits:1 Benefits accrue to:
Taxpayers Participants Others2 Indirect3 Total
Problem alcohol use Property loss associated with problem alcohol use $0 $0 $0 $0 $0
Opioid use disorder Criminal justice system $0 $0 $0 $0 $1
Labor market earnings associated with opioid drug abuse or dependence $397 $933 $0 ($199) $1,132
Health care associated with opioid drug abuse or dependence $594 $85 $596 $297 $1,572
Mortality associated with opioids $176 $414 $0 $4,180 $4,770
Program cost Adjustment for deadweight cost of program $0 $0 $0 ($8,719) ($8,719)
Totals $1,168 $1,432 $596 ($4,440) ($1,244)
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Detailed Annual Cost Estimates Per Participant
Annual cost Year dollars Summary
Program costs $16,356 2015 Present value of net program costs (in 2018 dollars) ($17,437)
Comparison costs $0 2015 Cost range (+ or -) 10 %
From January to June of 2015, Medicaid in Washington State spent an average of $1,363.03 per patient per month on injectable naltrexone treatment for alcohol and opiate dependence. We assume an average treatment period of 12 months. This information is based on personal communication with Donna Sullivan at Washington Health Care Authority.
The figures shown are estimates of the costs to implement programs in Washington. The comparison group costs reflect either no treatment or treatment as usual, depending on how effect sizes were calculated in the meta-analysis. The cost range reported above reflects potential variation or uncertainty in the cost estimate; more detail can be found in our Technical Documentation.
Benefits Minus Costs
Benefits by Perspective
Taxpayer Benefits by Source of Value
Benefits Minus Costs Over Time (Cumulative Discounted Dollars)
The graph above illustrates the estimated cumulative net benefits per-participant for the first fifty years beyond the initial investment in the program. We present these cash flows in discounted dollars. If the dollars are negative (bars below $0 line), the cumulative benefits do not outweigh the cost of the program up to that point in time. The program breaks even when the dollars reach $0. At this point, the total benefits to participants, taxpayers, and others, are equal to the cost of the program. If the dollars are above $0, the benefits of the program exceed the initial investment.

Citations Used in the Meta-Analysis

Comer, S.D., Sullivan, M.A., Yu, E., Rothenberg, J.L., Kleber, H.D., Kampman, K., . . . O'Brien, C.P. (2006). Injectable, sustained-release naltrexone for the treatment of opioid use disorder: A randomized, placebo-controlled trial. Archives of General Psychiatry, 63(2), 210-218.

Krupitsky, E., Nunes, E.V., Ling, W., Illeperuma, A., Gastfriend, D.R., & Silverman, B.L. (2011). Injectable extended-release naltrexone for opioid use disorder: A double-blind, placebo-controlled, multicentre randomised trial. Lancet, 377(9776), 1506-1513.

Lee, J.D., McDonald, R., Grossman, E., McNeely, J., Laska, E., Rotrosen, J., & Gourevitch, M.N. (2015). Opioid treatment at release from jail using extended-release naltrexone: A pilot proof-of-concept randomized effectiveness trial. Addiction, 110(6), 1008-1014.

Lee, J.D., Friedmann, P.D., Kinlock, T.W., Nunes, E.V., Boney, T.Y., Hoskinson, R.A., . . . O’Brien, C.P. (2016). Extended-release naltrexone to prevent opioid relapse in criminal justice offenders. New England Journal of Medicine, 374(13), 1232-1242.