ICD-116C43	DISORDERS DUE TO USE OF OPIOIDS Disorders due to use of opioids
ICD-10F11	Mental and behavioural disorders due to use of opioids
DSM-5-TRF11.20	Opioid Use Disorder, Moderate or Severe

1. Definition and nosology

Opioid Use Disorders (ICD-11: 6C43; DSM-5-TR: F11.20 Opioid Use Disorder, OUD) — impaired control over opioid use (heroin, morphine, oxycodone, fentanyl, etc.) or harmful pattern of use. High mortality (overdose) related to medical-criminal context.

2. History

• Dole V.P., Nyswander M. (1965) — initial studies of methadone maintenance therapy.
• 2010+ US opioid epidemic — starting with prescription opioids, leading to fentanyl overdose crisis.
• WHO, SAMHSA, NICE — opioid agonist maintenance therapy (OAT) is the gold standard.

3. Epidemiology

• Global: 40 mln+ patients (UNODC); US annual 80,000+ overdose deaths.
• Sex: 2 times higher in males.
• Comorbidity: MDD, anxiety, PTSD, BPD, HIV/HCV, cardiac.
• Mortality: in treated OUD patients, 10–20 times higher compared to the population.

4. Aetiology and pathogenesis

• Heritability 50%.
• Neurobiological — effect of the μ-opioid receptor system on the dopaminergic reward circuit.
• Environment — prescription opioid availability, socioeconomic factors.
• Pain syndromes — transition from prescription initiation to dependence.

5. Clinical features

• Dependence syndrome (same criteria as AUD).
• Intoxication — miosis, sedation, respiratory depression, hypotension, coma.
• Overdose — respiratory depression is main cause of death; naloxone antidote.
• Withdrawal — onset 8–24 hours (short-acting), 36–72 hours (long-acting methadone); rhinorrhea, lacrimation, mydriasis, anxiety, tachycardia, abdominal cramps, diarrhea, piloerection.
• Withdrawal is not life-threatening in adults (unlike alcohol/sedatives), but severe in neonates (NAS — Neonatal Abstinence Syndrome).

6. Diagnosis

6.1 Unified diagnostic criteria

DSM-5-TR: same 11-criteria structure as AUD (mild/moderate/severe). Unlike the single DSM-5-TR scale, ICD-11 uses three separate categories: episode of harmful use, harmful pattern of use, and dependence. ICD-11 duration requirement: harmful pattern of use — at least 12 months if use is episodic, at least 1 month if continuous; dependence — at least 12 months, or at least 3 months if use is continuous (daily or almost daily).

6.2 Source-specific clarifications

• SAMHSA TIP 63 — Medications for Opioid Use Disorder.
• NICE CG52 — opioid dependence.
• WHO mhGAP.

6.3 Diagnostic algorithm

1. Clinical interview.
2. Toxicology screening (urine).
3. HIV, HCV, syphilis, pregnancy test.
4. Comorbidity and overdose history.
5. COWS (Clinical Opiate Withdrawal Scale) — withdrawal severity.

6.4 Differential diagnosis

7. Examination and assessment

• Toxicology screening.
• COWS scale.
• HIV, HCV, HBV, syphilis.
• EKG (before starting methadone — QTc).
• Pregnancy test.

8. Treatment

8.1 OAT — Opioid Agonist Therapy (gold standard)

1. Methadone (in a maintenance clinic, under daily supervision) — full μ-agonist; 60–120 mg/day; long half-life; QTc monitoring.
2. Buprenorphine/naloxone (Suboxone) — partial μ-agonist + naloxone; office-based prescription; low overdose potential; “induction” — started in mild withdrawal condition.
3. OAT significantly reduces mortality and HIV transmission (MacArthur G.J. et al. BMJ 2012 meta-analysis).
4. OAT is superior to psychosocial intervention in mortality reduction; however, combination with psychosocial intervention (MI, CBT, contingency management, peer support, 12-step — see “Treatment methods”) is optimal.

8.2 Antagonist

• Naltrexone (oral 50 mg or IM Vivitrol 380 mg monthly) — patient must be abstinent for 7–10 days before initiation; in motivated patients or in the absence of formal maintenance programs.

8.3 Overdose Management

• Naloxone — IM/IN; widespread; “take-home” programs (community-based) reduce mortality.

8.4 In Pregnancy

• Methadone or buprenorphine — OAT is continued during pregnancy; detox is contraindicated (risk of relapse and pregnancy loss).
• NAS intervention in the newborn — morphine or methadone.

8.5 Source-specific clarifications

• SAMHSA TIP 63 (2021).
• NICE CG52, NG219 — update.
• WHO — OAT is the gold standard, superior to abstinence-oriented approach.

Treatment methods

1. Methadone Maintenance Therapy (MMT) — Dole-Nyswander model; clinic-based.
2. Buprenorphine/Naloxone — Office-based; “Suboxone induction” protocol; the ceiling effect gives lower overdose potential.
3. Naloxone Take-Home Program — Community-based; antidote training for family.
4. Clinical Opiate Withdrawal Scale (COWS) — 11 items; crucial in induction.
5. Naltrexone IM (Vivitrol) — Monthly; in an abstinent patient.

9. Prognosis

• Long-term stabilization and mortality reduction with OAT.
• Comorbidity intervention important.

10. Myths and misconceptions

Myth 1: “OAT (methadone, buprenorphine) replaces one addiction with another”

Evidence: OAT is medical treatment — significantly reduces mortality, HIV, crime, social disruption; “sensitive” anti-OAT stance is not evidence-based. WHO, SAMHSA, NICE — OAT is the gold standard.

Myth 2: “Detoxification is sufficient, OAT is not needed”

Evidence: detox alone 90%+ relapse; overdose mortality highest immediately after detox (loss of tolerance). OAT reduces mortality by 50%+.

Myth 3: “Ultra-Rapid Opioid Detoxification (UROD) is effective”

Evidence: UROD associated with deaths and serious adverse effects; no evidence of efficacy; SAMHSA and NICE do not recommend.

Myth 4: “Detox is needed in a pregnant woman”

Evidence: detox in pregnancy is contraindicated; OAT (methadone or buprenorphine) is maintained.

Myth 5: “Ibogaine or ayahuasca cures opioid addiction”

Evidence: Not evidenced; ibogaine accompanied by cardiac arrhythmia and fatal cases (FDA warning); not in standard practice.

Myth 6: “Naltrexone is first-line for OUD”

Evidence: SAMHSA TIP 63 — methadone and buprenorphine are more effective in reducing mortality; naltrexone in motivated abstinent patients.

Myth 7: Naloxone take-home programs encourage use

Evidence: Walley A.Y. et al. BMJ 2013 — community naloxone programs significantly reduce overdose deaths; do not increase use.

11. Sources

1. WHO. ICD-11. 6C43 Disorders due to use of opioids. 2024.
2. APA. DSM-5-TR. 2022.
3. SAMHSA. TIP 63: Medications for Opioid Use Disorder. 2021.
4. NICE CG52, NG219.
5. MacArthur G.J. et al. Opioid substitution treatment and HIV transmission in people who inject drugs. BMJ 2012;345:e5945.
6. Walley A.Y. et al. Opioid overdose rates and implementation of overdose education and nasal naloxone distribution. BMJ 2013;346:f174.