Overview & types

Opioids include prescription analgesics (e.g., morphine, oxycodone), heroin and synthetic opioids (fentanyl and analogues). OUD ranges from problematic use and dependence to severe disorder with medical, social and legal harms.

Recognition — signs and symptoms

• Behavioural: drug-seeking, multiple prescriptions, reduced social/occupational functioning, withdrawal avoidance.
• Physical: constricted pupils (miosis), drowsiness, slurred speech, track marks if injecting, constipation, infections related to injecting.
• Withdrawal: anxiety, yawning, lacrimation, rhinorrhoea, myalgia, piloerection, diarrhoea, nausea, insomnia—usually begins 6–48 hours (short‑acting) or 24–72 hours (long‑acting) after last dose.

Assessment checklist

1. Substance history: type of opioid, dose, route, frequency, duration, last use, and other substances (alcohol, benzodiazepines).
2. Risk factors: prior overdose, injecting, co‑existing psychiatric disorder, polysubstance use, pregnancy, limited supports.
3. Physical exam: vitals, pupils, signs of injection, infection; mental state exam and suicide risk assessment.
4. Investigations as indicated: urine drug screen, serology (HIV, hepatitis B/C), pregnancy test, baseline labs.

Overdose recognition & immediate management

• Signs of opioid overdose: reduced consciousness, pinpoint pupils, respiratory depression (slow/shallow respirations), cyanosis.
• Immediate steps: call emergency services, support airway and breathing, give high‑flow oxygen, and administer naloxone (intranasal or IV/IM) titrated to restore adequate ventilation without precipitating severe withdrawal.
• Post‑naloxone: monitor for re‑sedation as naloxone effect may wear off earlier than long‑acting opioids; observe for at least 2–4 hours or admit based on risk.
• Provide brief harm reduction counselling and offer linkage to treatment services before discharge when appropriate.

Opioid withdrawal management

• Symptomatic treatments: clonidine or lofexidine for autonomic symptoms, antiemetics, antidiarrheals, NSAIDs for myalgia, and sleep aids where appropriate.
• Consider rapid buprenorphine induction for patients seeking treatment — ensure patient is in moderate withdrawal (COWS ≥8) to avoid precipitated withdrawal.
• Methadone maintenance is effective for stabilisation but requires supervised dosing and appropriate regulatory framework.
• For severe dependence or medical complications, consider inpatient detoxification with multidisciplinary support.

Opioid agonist treatment (OAT)

• Buprenorphine (sublingual or buprenorphine–naloxone): partial agonist with ceiling effect on respiratory depression — good safety profile; requires correct induction protocols.
• Methadone: full agonist effective for retention and reducing illicit use — requires careful dosing and monitoring due to QTc prolongation and overdose risk.
• Choice depends on patient factors, availability, comorbidity, pregnancy (methadone preferred in many settings), and local regulations.
• OAT should be accompanied by psychosocial support, regular reviews and management of comorbid conditions.

Psychosocial interventions

• Evidence‑based options: cognitive behavioural therapy, contingency management, motivational interviewing, and structured relapse prevention programmes.
• Address social determinants: housing, employment, legal support and family involvement where safe and appropriate.
• Peer support and mutual‑help groups (e.g., Narcotics Anonymous) can augment formal treatment.

Harm reduction

• Provide and train on naloxone for patients, families and peers — intranasal or intramuscular formulations where available.
• Needle and syringe programs (NSP), supervised consumption sites (where available), vaccination (HBV), and testing/treatment for HIV and HCV.
• Avoid polysubstance mixing, especially benzodiazepines and alcohol, which increase overdose risk.

Special populations

• Pregnancy: Continue or initiate OAT (methadone or buprenorphine) rather than abrupt detox; coordinate obstetric and addiction care.
• Adolescents: involve family, use age‑appropriate psychosocial interventions and consider OAT in severe cases with specialist input.
• Pain patients: assess for opioid use disorder vs iatrogenic dependence; prioritize multimodal pain management and close monitoring if opioids continued.

Key takeaways

• Recognise OUD early — assess risk, screen for comorbidity and offer evidence‑based treatments.
• Overdose is preventable — naloxone distribution and harm reduction reduce mortality.
• OAT (buprenorphine or methadone) plus psychosocial support is the standard of care for moderate‑severe OUD.
• Coordinate multidisciplinary care, address social needs and tailor treatment to individual patient preferences and risks.