Medications for Opioid Use Disorder
link to page 1 
Updated April 14, 2023
Medications for Opioid Use Disorder
Opioids, such as heroin, fentanyl, and some prescription
different from naloxone (e.g., Narcan), which is used to
pain medications (including morphine and oxycodone) are
reverse opioid overdose, but not used to treat opioid use
substances that act on receptors in the brain important in
disorders.
regulating pain and emotion. Opioids have high potential
for misuse, dependence, and overdose. The label opioid use
Regulatory Framework
disorder (OUD) is the diagnostic term for “a problematic
Two overlapping systems of federal law apply to MOUD:
pattern of opioid use leading to clinically significant
one regulating pharmaceuticals and the other regulating
impairment or distress,” as defined in the Diagnostic and
controlled substances.
Statistical Manual of Mental Disorders (DSM-5-TR).
Federal Food, Drug, and Cosmetic Act (FFDCA)
Medications for Opioid Use Disorder
Under the Federal Food, Drug, and Cosmetic Act (FFDCA,
Research on OUD has generally found that the most
21 U.S.C. §§301 et seq.), the Food and Drug
effective treatments involve the use of certain medications.
Administration (FDA) in the Department of Health and
Three medications are currently used to treat OUD:
Human Services (HHS) has primary responsibility for
methadone, buprenorphine, and naltrexone. Medications for
ensuring the safety and effectiveness of pharmaceuticals,
opioid use disorder (MOUD) are often combined with other
regardless of whether they are controlled substances. (For
services, such as counseling. (MOUD is also referred to as
more information, see CRS Report R41983, How FDA
medication-assisted treatment [MAT] for OUD.)
Approves Drugs and Regulates Their Safety and
Effectiveness.) Methadone, buprenorphine, and naltrexone
Methadone and buprenorphine are both opioids; their use to
are subject to the FFDCA.
treat opioid use disorder is often called opioid substitution
therapy, opioid replacement therapy, or opioid agonist
Controlled Substances Act (CSA)
treatment. These medications can reduce the cravings and
Under the Controlled Substances Act (CSA, 21 U.S.C.
withdrawal symptoms that often accompany
§§801 et seq.), the Drug Enforcement Administration
discontinuation of misused opioids, typically without
(DEA) in the Department of Justice (DOJ) has primary
producing the same euphoria or “high” as the substances
responsibility for regulating the use of controlled
they replace.
substances for legitimate medical, scientific, research, and
industrial purposes, and for preventing these substances
Methadone
from being diverted for illegal purposes. The CSA assigns
Methadone is a full opioid agonist, meaning it binds to and
various drugs and other substances to one of five schedules
activates opioid receptors in the brain. Methadone carries
based on accepted medical use, potential for misuse, and
risk of misuse but poses fewer risks of dependence and
severity of potential psychological or physical dependence.
overdose than some other full opioid agonists (e.g., heroin).
Schedule I contains substances that have no currently
Methadone suppresses withdrawal symptoms in
accepted medical use and are not available by prescription
detoxification therapy and controls the craving for opioids
(such as heroin). Schedules II, III, IV, and V include
in maintenance therapy.
substances that have recognized medical uses and are
progressively less dangerous and pose fewer risks. As
Buprenorphine
shown in Table 1, methadone, buprenorphine, and
Buprenorphine is a partial opioid agonist, meaning it binds
naltrexone are classified differently under the CSA. For
to opioid receptors in the brain and activates them, but not
more information, see CRS Report R45948, The Controlled
as much as full opioid agonists. Buprenorphine also carries
Substances Act (CSA): A Legal Overview for the 118th
risk of misuse but poses fewer risks of dependence and
Congress.
overdose than full opioid agonists. Like methadone,
buprenorphine is used for detoxification and maintenance
Table 1. FDA-Approved Medications for Opioid MAT
therapy.
Medication
Class
CSA Schedule
Naltrexone
Methadone
Ful Opioid Agonist
II
Naltrexone is an opioid antagonist, meaning it binds to
Buprenorphine Partial Opioid Agonist III
opioid receptors but does not activate them; it prevents
Naltrexone
Opioid Antagonist
none
opioid agonists from binding to and activating opioid
Source: Congressional Research Service based on information
receptors. Naltrexone carries no known risk of misuse.
publicly available from FDA and DEA.
Naltrexone is used for relapse prevention because an
individual on naltrexone who uses opioids will not
Under the CSA, responsibility for regulating schedule II
experience the effects of those opioids. Naltrexone is
MOUD (i.e., methadone) falls to both DEA in DOJ and the
https://crsreports.congress.gov
Medications for Opioid Use Disorder
Substance Abuse and Mental Health Services
who handles controlled substances. OTPs must also comply
Administration (SAMHSA) in HHS. The CSA requires
with relevant DEA regulations addressing records
most persons who handle controlled substances to register
maintenance, security controls, and other matters. They
with DEA. It further requires individuals treating OUD with
must also comply with any applicable state laws.
methadone to obtain a separate DEA registration but leaves
specific criteria for obtaining this registration up to the
COVID-19 OTP Flexibilities
executive agencies.
During the COVID-19 public health emergency (PHE),
SAMHSA and DEA allowed greater flexibilities for take-
Opioid Treatment Programs (OTPs)
home methadone. Beginning in March 2020 and throughout
The use of methadone to treat OUD is subject to federal
the duration of the PHE, SAMHSA has allowed states to
regulations beyond those that apply to the same medication
request a “blanket exception for all stable patients in an
used for other purposes (e.g., treating pain) or other
OTP to receive 28 days of take-home doses” or 14 days for
controlled substances. Both DEA and SAMHSA
patients who are less stable. SAMHSA is currently
promulgate rules for methadone treatment provided at
considering mechanisms to make this flexibility permanent
federally certified opioid treatment programs (OTPs;
after the PHE expires.
known as narcotic treatment programs in DEA lexicon).
Requirements for OTPs are specified in the Code of
Office-Based Opioid Treatment
Federal Regulations (21 C.F.R. Chapter II and 42 C.F.R.
The use of buprenorphine and naltrexone outside of an OTP
Part 8).
is often referred to as office-based opioid treatment
(OBOT) or office-based MOUD (though it may occur in
According to these regulations, OTPs must obtain
various settings). Office-based opioid treatment is not
subject to the same regulations governing OTPs. The use of
accreditation from a SAMHSA-approved accreditor,
buprenorphine in OBOT is subject to CSA provisions
certification from SAMHSA, and
regulating controlled substances in medical treatment or
telemedicine generally.
registration from DEA.
Prior to the December 2022 enactment of the Restoring
Programs meeting all requirements may “administer or
Hope for Mental Health and Well-Being Act (Division FF,
dispense directly (but not prescribe)” any drug approved by
Title I of P.L. 117-328, the Consolidated Appropriations
FDA for treatment of opioid use disorder. They may also
Act, 2023), practitioners meeting certain criteria were
administer a drug being studied for treatment of OUD, as
required to obtain a separate waiver via DEA and
authorized by FDA under an investigational new drug
SAMHSA (known as a DATA waiver or X waiver) in order
application.
to treat OUD with buprenorphine outside of an OTP.
Practitioners with DATA waivers were subject to limits on
With few exceptions, the use of methadone to treat OUD is
the number of patients they could treat at any time. P.L.
limited to OTPs, which may also offer other MOUD,
117-328 repealed the DATA waiver requirement and
including buprenorphine for detoxification or maintenance
patient limit. Thus, under current law, any practitioner
and naltrexone for relapse prevention. OTPs generally
registered with DEA to dispense (i.e., prescribe or
administer methadone on a daily basis, with staff observing
administer) controlled substances is authorized to use
as a patient takes an oral dose of liquid methadone. Stable
buprenorphine to treat OUD outside of an OTP, subject to
patients may be allowed to receive a few take-home doses
state laws.
(e.g., for a weekend or longer).
Naltrexone is not a controlled substance and therefore its
OTP Accreditation
use is not governed by the CSA. Any practitioner with
Accreditation is based on a peer review process in which
prescribing authority (as determined by the state) can use
SAMHSA-approved accrediting organizations evaluate
naltrexone in the treatment of OUD.
OTPs by making site visits and reviewing policies,
procedures, and practices. Examples of accrediting
COVID-19 OBOT Telemedicine Flexibilities
organizations include The Joint Commission and the
Prior to the COVID-19 PHE, practitioners initiating patients
Commission on Accreditation of Rehabilitation Facilities.
with buprenorphine for OUD were required to conduct an
in-person medical evaluation (21 U.S.C. §829). During the
OTP Certification
COVID-19 PHE, SAMHSA and DEA allowed practitioners
Certification is based on SAMHSA’s determination that an
to prescribe buprenorphine via telemedicine without first
accredited program is qualified to carry out treatment
conducting such evaluation. In March 2023, DEA issued a
conforming to standards in federal regulation. SAMHSA
proposed rule that would permanently allow practitioners to
uses the results of the accreditation process as well as other
initiate patients with buprenorphine for OUD via
information to determine whether a program is qualified.
telemedicine without first conducting an in-person
SAMHSA promulgates guidelines to help accrediting
evaluation, provided such evaluation took place within 30
organizations and OTPs conform to treatment standards.
days (88 FR 12890).
OTP Registration
Registration with DEA as an OTP is separate from—and in
Johnathan H. Duff, Analyst in Health Policy
addition to—the DEA registration required of any “person”
IF12348
(including a hospital, pharmacy, or doctor, among others)
https://crsreports.congress.gov
Medications for Opioid Use Disorder
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF12348 · VERSION 3 · UPDATED
Updated April 14, 2023
Medications for Opioid Use Disorder
Opioids, such as heroin, fentanyl, and some prescription
different from naloxone (e.g., Narcan), which is used to
pain medications (including morphine and oxycodone) are
reverse opioid overdose, but not used to treat opioid use
substances that act on receptors in the brain important in
disorders.
regulating pain and emotion. Opioids have high potential
for misuse, dependence, and overdose. The label opioid use
Regulatory Framework
disorder (OUD) is the diagnostic term for “a problematic
Two overlapping systems of federal law apply to MOUD:
pattern of opioid use leading to clinically significant
one regulating pharmaceuticals and the other regulating
impairment or distress,” as defined in the Diagnostic and
controlled substances.
Statistical Manual of Mental Disorders (DSM-5-TR).
Federal Food, Drug, and Cosmetic Act (FFDCA)
Medications for Opioid Use Disorder
Under the Federal Food, Drug, and Cosmetic Act (FFDCA,
Research on OUD has generally found that the most
21 U.S.C. §§301 et seq.), the Food and Drug
effective treatments involve the use of certain medications.
Administration (FDA) in the Department of Health and
Three medications are currently used to treat OUD:
Human Services (HHS) has primary responsibility for
methadone, buprenorphine, and naltrexone. Medications for
ensuring the safety and effectiveness of pharmaceuticals,
opioid use disorder (MOUD) are often combined with other
regardless of whether they are controlled substances. (For
services, such as counseling. (MOUD is also referred to as
more information, see CRS Report R41983, How FDA
medication-assisted treatment [MAT] for OUD.)
Approves Drugs and Regulates Their Safety and
Effectiveness.) Methadone, buprenorphine, and naltrexone
Methadone and buprenorphine are both opioids; their use to
are subject to the FFDCA.
treat opioid use disorder is often called opioid substitution
therapy, opioid replacement therapy, or opioid agonist
Controlled Substances Act (CSA)
treatment. These medications can reduce the cravings and
Under the Controlled Substances Act (CSA, 21 U.S.C.
withdrawal symptoms that often accompany
§§801 et seq.), the Drug Enforcement Administration
discontinuation of misused opioids, typically without
(DEA) in the Department of Justice (DOJ) has primary
producing the same euphoria or “high” as the substances
responsibility for regulating the use of controlled
they replace.
substances for legitimate medical, scientific, research, and
industrial purposes, and for preventing these substances
Methadone
from being diverted for illegal purposes. The CSA assigns
Methadone is a full opioid agonist, meaning it binds to and
various drugs and other substances to one of five schedules
activates opioid receptors in the brain. Methadone carries
based on accepted medical use, potential for misuse, and
risk of misuse but poses fewer risks of dependence and
severity of potential psychological or physical dependence.
overdose than some other full opioid agonists (e.g., heroin).
Schedule I contains substances that have no currently
Methadone suppresses withdrawal symptoms in
accepted medical use and are not available by prescription
detoxification therapy and controls the craving for opioids
(such as heroin). Schedules II, III, IV, and V include
in maintenance therapy.
substances that have recognized medical uses and are
progressively less dangerous and pose fewer risks. As
Buprenorphine
shown in Table 1, methadone, buprenorphine, and
Buprenorphine is a partial opioid agonist, meaning it binds
naltrexone are classified differently under the CSA. For
to opioid receptors in the brain and activates them, but not
more information, see CRS Report R45948, The Controlled
as much as full opioid agonists. Buprenorphine also carries
Substances Act (CSA): A Legal Overview for the 118th
risk of misuse but poses fewer risks of dependence and
Congress.
overdose than full opioid agonists. Like methadone,
buprenorphine is used for detoxification and maintenance
Table 1. FDA-Approved Medications for Opioid MAT
therapy.
Medication
Class
CSA Schedule
Naltrexone
Methadone
Ful Opioid Agonist
II
Naltrexone is an opioid antagonist, meaning it binds to
Buprenorphine Partial Opioid Agonist III
opioid receptors but does not activate them; it prevents
Naltrexone
Opioid Antagonist
none
opioid agonists from binding to and activating opioid
Source: Congressional Research Service based on information
receptors. Naltrexone carries no known risk of misuse.
publicly available from FDA and DEA.
Naltrexone is used for relapse prevention because an
individual on naltrexone who uses opioids will not
Under the CSA, responsibility for regulating schedule II
experience the effects of those opioids. Naltrexone is
MOUD (i.e., methadone) falls to both DEA in DOJ and the
https://crsreports.congress.gov
Medications for Opioid Use Disorder
Substance Abuse and Mental Health Services
who handles controlled substances. OTPs must also comply
Administration (SAMHSA) in HHS. The CSA requires
with relevant DEA regulations addressing records
most persons who handle controlled substances to register
maintenance, security controls, and other matters. They
with DEA. It further requires individuals treating OUD with
must also comply with any applicable state laws.
methadone to obtain a separate DEA registration but leaves
specific criteria for obtaining this registration up to the
COVID-19 OTP Flexibilities
executive agencies.
During the COVID-19 public health emergency (PHE),
SAMHSA and DEA allowed greater flexibilities for take-
Opioid Treatment Programs (OTPs)
home methadone. Beginning in March 2020 and throughout
The use of methadone to treat OUD is subject to federal
the duration of the PHE, SAMHSA has allowed states to
regulations beyond those that apply to the same medication
request a “blanket exception for all stable patients in an
used for other purposes (e.g., treating pain) or other
OTP to receive 28 days of take-home doses” or 14 days for
controlled substances. Both DEA and SAMHSA
patients who are less stable. SAMHSA is currently
promulgate rules for methadone treatment provided at
considering mechanisms to make this flexibility permanent
federally certified opioid treatment programs (OTPs;
after the PHE expires.
known as narcotic treatment programs in DEA lexicon).
Requirements for OTPs are specified in the Code of
Office-Based Opioid Treatment
Federal Regulations (21 C.F.R. Chapter II and 42 C.F.R.
The use of buprenorphine and naltrexone outside of an OTP
Part 8).
is often referred to as office-based opioid treatment
(OBOT) or office-based MOUD (though it may occur in
According to these regulations, OTPs must obtain
various settings). Office-based opioid treatment is not
subject to the same regulations governing OTPs. The use of
accreditation from a SAMHSA-approved accreditor,
buprenorphine in OBOT is subject to CSA provisions
certification from SAMHSA, and
regulating controlled substances in medical treatment or
telemedicine generally.
registration from DEA.
Prior to the December 2022 enactment of the Restoring
Programs meeting all requirements may “administer or
Hope for Mental Health and Well-Being Act (Division FF,
dispense directly (but not prescribe)” any drug approved by
Title I of P.L. 117-328, the Consolidated Appropriations
FDA for treatment of opioid use disorder. They may also
Act, 2023), practitioners meeting certain criteria were
administer a drug being studied for treatment of OUD, as
required to obtain a separate waiver via DEA and
authorized by FDA under an investigational new drug
SAMHSA (known as a DATA waiver or X waiver) in order
application.
to treat OUD with buprenorphine outside of an OTP.
Practitioners with DATA waivers were subject to limits on
With few exceptions, the use of methadone to treat OUD is
the number of patients they could treat at any time. P.L.
limited to OTPs, which may also offer other MOUD,
117-328 repealed the DATA waiver requirement and
including buprenorphine for detoxification or maintenance
patient limit. Thus, under current law, any practitioner
and naltrexone for relapse prevention. OTPs generally
registered with DEA to dispense (i.e., prescribe or
administer methadone on a daily basis, with staff observing
administer) controlled substances is authorized to use
as a patient takes an oral dose of liquid methadone. Stable
buprenorphine to treat OUD outside of an OTP, subject to
patients may be allowed to receive a few take-home doses
state laws.
(e.g., for a weekend or longer).
Naltrexone is not a controlled substance and therefore its
OTP Accreditation
use is not governed by the CSA. Any practitioner with
Accreditation is based on a peer review process in which
prescribing authority (as determined by the state) can use
SAMHSA-approved accrediting organizations evaluate
naltrexone in the treatment of OUD.
OTPs by making site visits and reviewing policies,
procedures, and practices. Examples of accrediting
COVID-19 OBOT Telemedicine Flexibilities
organizations include The Joint Commission and the
Prior to the COVID-19 PHE, practitioners initiating patients
Commission on Accreditation of Rehabilitation Facilities.
with buprenorphine for OUD were required to conduct an
in-person medical evaluation (21 U.S.C. §829). During the
OTP Certification
COVID-19 PHE, SAMHSA and DEA allowed practitioners
Certification is based on SAMHSA’s determination that an
to prescribe buprenorphine via telemedicine without first
accredited program is qualified to carry out treatment
conducting such evaluation. In March 2023, DEA issued a
conforming to standards in federal regulation. SAMHSA
proposed rule that would permanently allow practitioners to
uses the results of the accreditation process as well as other
initiate patients with buprenorphine for OUD via
information to determine whether a program is qualified.
telemedicine without first conducting an in-person
SAMHSA promulgates guidelines to help accrediting
evaluation, provided such evaluation took place within 30
organizations and OTPs conform to treatment standards.
days (88 FR 12890).
OTP Registration
Registration with DEA as an OTP is separate from—and in
Johnathan H. Duff, Analyst in Health Policy
addition to—the DEA registration required of any “person”
IF12348
(including a hospital, pharmacy, or doctor, among others)
https://crsreports.congress.gov
Medications for Opioid Use Disorder
Disclaimer
This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to
congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.
Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has
been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the
United States Government, are not subject to copyright protection in the United States. Any CRS Report may be
reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include
copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you
wish to copy or otherwise use copyrighted material.
https://crsreports.congress.gov | IF12348 · VERSION 3 · UPDATED