Opioid Use Disorder (OUD)
Problematic opioid use meeting >=2 of 11 DSM-5-TR criteria in 12 months; high overdose mortality.
Also known as: OUD, opioid addiction, heroin use disorder, prescription opioid misuse
Overview
A pattern of opioid use leading to clinically significant impairment or distress, defined by >=2 of 11 DSM-5-TR criteria within 12 months. Tolerance and withdrawal in the context of appropriate medical use do not count toward criteria.
Epidemiology
~6-9 million US adults with past-year OUD. Overdose deaths driven by fentanyl contamination of heroin and counterfeit pills. Disproportionate impact on rural communities and certain demographic groups.
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Risk factors
- Personal/family history of SUD, mental illness
- Chronic pain with prolonged opioid prescribing
- Adolescent initiation of nonmedical opioid use
- History of trauma, ACEs
- Social/economic instability, incarceration
- Concurrent benzodiazepine or alcohol use (markedly raises overdose risk)
Pathophysiology
Mu-opioid receptor agonism produces analgesia, euphoria, and respiratory depression. Chronic exposure leads to receptor desensitization, upregulated cAMP signaling, and noradrenergic adaptation in locus coeruleus — basis for withdrawal phenomena.
Clinical presentation
Symptoms
- Intoxication: euphoria, miosis, drowsiness, slurred speech, hypoventilation, decreased GI motility
- Overdose: pinpoint pupils, respiratory depression (rate <12 or apnea), depressed consciousness — classic triad
- Withdrawal: dysphoria, lacrimation, rhinorrhea, yawning, piloerection, mydriasis, myalgias, GI distress, autonomic hyperactivity — uncomfortable but rarely life-threatening in adults (dangerous in neonates and frail)
- DSM-5-TR criteria parallel other SUDs
Signs / physical exam
- Track marks, abscesses, endocarditis murmur
- Constipation, dental disease, weight loss
- Neonatal abstinence syndrome — irritability, high-pitched cry, tremor, feeding difficulties
Differential diagnosis
- Chronic pain syndrome — Pain-driven use within prescribed parameters; consider OUD if criteria met beyond physical dependence
- Other SUD — Polysubstance use is common; assess for alcohol, benzodiazepine, stimulant use
- Mood/anxiety/PTSD — Frequent comorbidity; treat concurrently
- Sepsis, hypoglycemia, intracranial pathology — Differential for altered mental status — do not anchor on suspected overdose
Diagnostic workup
Diagnostic criteria
DSM-5-TR: A problematic pattern of opioid use causing impairment/distress, with >=2 of 11 criteria in 12 months. Tolerance/withdrawal under appropriately supervised opioid therapy do not count. Severity by criterion count as in other SUDs.
Labs
- Urine drug screen (note: synthetic opioids including fentanyl and methadone require specific testing)
- Hepatitis B/C, HIV, syphilis screening
- CBC, CMP
- Pregnancy test
- ECG if methadone use (QT prolongation)
Imaging
- TTE if endocarditis suspected
- CT head for trauma/altered mental status
Diagnostic algorithm
| MOUD | Mechanism | Setting | Key caveat |
|---|---|---|---|
| Buprenorphine | Partial mu agonist | Office-based | Precipitated withdrawal if started too early |
| Methadone | Full mu agonist | OTP only | QT prolongation; high tolerance & pregnancy |
| Naltrexone XR | Mu antagonist | Office-based | Requires 7-10 day opioid-free interval |
Treatment
First-line
- Medications for OUD (MOUD) — first-line and lifesaving: buprenorphine (partial mu agonist; sublingual film/tablet or monthly SC injection sublocade), methadone (full mu agonist; opioid treatment program only), or naltrexone XR (mu antagonist; requires opioid-free interval)
- Buprenorphine can now be prescribed by any DEA-registered clinician (X-waiver eliminated 2023 MAT Act) — induce when patient in moderate withdrawal (COWS >=8-12) to avoid precipitated withdrawal
- Methadone reduces all-cause mortality and is preferred for high-tolerance patients and pregnancy
- Counseling, contingency management, peer support (NA, SMART Recovery)
- Naloxone distribution to patient and household — IM/IN, repeat as needed
- Harm reduction: syringe service programs, fentanyl test strips, never use alone
Overdose
- ABC, ventilatory support
- Naloxone 0.04-0.4 mg IV/IM/IN; repeat every 2-3 min; titrate to respiratory effort
- Observe for resedation — fentanyl/methadone may require infusion or repeated doses
- Refer to MOUD before discharge
Pregnancy
- Buprenorphine (mono-product) or methadone — withdrawal is harmful to fetus
- Avoid medication-free detoxification
- Coordinate prenatal care, monitor for neonatal abstinence syndrome
- Breastfeeding compatible with both medications
Second-line / adjunct
- Naltrexone XR 380 mg IM monthly — requires 7-10 day opioid-free interval; lower retention than agonist therapy
- Inpatient detoxification only as bridge to MOUD (high relapse and overdose risk after detox alone)
- Adjuncts for withdrawal: clonidine, lofexidine, loperamide, NSAIDs, ondansetron
Complications
- Overdose death — leading cause of accidental death in US adults
- Infectious: bacterial endocarditis, skin abscesses, osteomyelitis, HIV, hepatitis C
- Neonatal abstinence syndrome
- Hypogonadism, opioid-induced bowel dysfunction, hyperalgesia
- Mood and anxiety disorders, suicidality
- Incarceration, family disruption, financial collapse
PANCE pearls
- MOUD reduces all-cause mortality by ~50% — buprenorphine and methadone are first-line; do not withhold.
- Buprenorphine ceiling effect on respiratory depression makes it safer than methadone, but precipitated withdrawal can occur if initiated before adequate withdrawal (COWS >=8-12) — use 'micro-induction' for fentanyl-using patients.
- Stigma is a barrier to MOUD — avoid terms like 'addict,' 'clean,' 'dirty urine.'
- Co-prescribe and distribute naloxone for all patients on chronic opioids, MOUD, or with OUD history; train family/peers.
- Methadone: ECG for QTc at baseline, 30 days, annually; avoid combining with QT-prolonging drugs.
References
- SAMHSA TIP 63 — SAMHSA TIP 63: Medications for Opioid Use Disorder (2021)
- ASAM 2020 — American Society of Addiction Medicine National Practice Guideline for the Treatment of Opioid Use Disorder (2020)
- USPSTF 2020 — Screening for Unhealthy Drug Use: USPSTF Recommendation Statement. JAMA 2020
- DSM-5-TR — American Psychiatric Association. DSM-5-TR (2022)
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