What are the signs, symptoms, and treatment for opiate (opioid) poisoning?

Opioid Poisoning: Signs, Symptoms, and Treatment

For suspected opioid poisoning, immediately focus on airway management and ventilatory support while administering naloxone 0.4-2 mg IV every 2-3 minutes until respiratory rate normalizes to approximately 10 breaths/minute—the classic triad of respiratory depression (rate <8 breaths/min), CNS depression with somnolence, and pinpoint pupils confirms the diagnosis. 1, 2, 3

Clinical Presentation

Cardinal Signs (Classic Opioid Toxidrome)

• Respiratory depression: Decreased respiratory rate below 8 breaths/minute with increased expiratory pause and risk of apnea—this is the most life-threatening manifestation 1, 2, 3
• CNS depression: Progressive somnolence leading to loss of consciousness and loss of protective airway reflexes 2, 3
• Miosis: Pinpoint pupils (though this may be absent with certain synthetic opioids or in severe hypoxia) 4

Additional Clinical Features

• Cyanosis from hypoxemia 4
• Bradycardia and hypotension in severe cases 5
• Decreased bowel sounds 4
• Hypothermia 4

Critical pitfall: The absence of pinpoint pupils does not rule out opioid poisoning, particularly with fentanyl analogs or in the presence of hypoxic brain injury. 4

Immediate Management Algorithm

Step 1: Airway and Breathing (Absolute Priority)

Airway management and ventilatory support take absolute priority over naloxone administration. 1, 3

• For respiratory arrest with definite pulse: Immediately provide bag-mask ventilation or rescue breathing and maintain until spontaneous breathing returns 1, 2
• Open the airway and deliver rescue breaths, ideally with bag-mask or barrier device 1
• Continue standard BLS/ALS measures if spontaneous breathing does not return 1

Step 2: Naloxone Administration

Dosing strategy (titrate to respiratory effect, NOT full consciousness): 2, 3, 6

• Initial dose: 0.4-2 mg IV, repeating every 2-3 minutes 2, 3
• Alternative preparation: 0.4 mg diluted to 10 mL with saline, administered 1 mL IV every 2 minutes 2
• Goal: Respiratory rate ≥10 breaths/minute while preserving some analgesia 2, 3
• Lower doses (0.04-0.4 mg): Consider in known opioid-dependent patients to minimize precipitating acute withdrawal syndrome 3, 6

Routes of administration: 7

• IV is preferred and most effective 7
• IM naloxone is more effective than intranasal (82% vs 63% response rate at 8 minutes) 7
• Intranasal can be used when IV/IM access is unavailable, though it requires higher cumulative doses 7

Step 3: Cardiac Arrest Management

For patients in cardiac arrest: Standard resuscitative measures with high-quality CPR (compressions plus ventilation) take priority over naloxone administration, as there is no proven benefit from naloxone in cardiac arrest. 1, 3

• Focus on high-quality CPR first 1
• Naloxone can be administered alongside standard care if it does not delay CPR components 1
• Do not delay activating emergency response systems while awaiting response to naloxone 1

Special Considerations for Synthetic Opioids

Fentanyl and high-potency synthetic opioids require special attention: 3

• Likely require higher cumulative naloxone doses due to high μ-opioid receptor affinity and slow dissociation kinetics 3
• May need repeated dosing or continuous infusion 3
• Extended observation periods are mandatory 3

Post-Resuscitation Monitoring

All patients must be observed in a healthcare setting until risk of recurrent opioid toxicity is low and vital signs have normalized (Class I recommendation). 1, 2, 3

Duration of observation varies by opioid type:

• Short-acting opioids: Minimum observation until naloxone effects wear off (30-90 minutes) 2
• Long-acting or sustained-release opioids (methadone, extended-release formulations): Prolonged observation for potentially fatal overdoses, as recurrent toxicity commonly occurs after initial naloxone response 2, 3
• Fentanyl: Extended monitoring due to high lipophilicity and potential for redistribution 3

Monitoring parameters:

• Respiratory rate and depth 2
• Level of consciousness 2
• Oxygen saturation 4
• Vital signs stability 2

Critical pitfall: The duration of action of many opioids exceeds that of naloxone, requiring repeated doses or continuous infusion. 1, 6

Management of Naloxone-Induced Withdrawal

Naloxone can precipitate acute opioid withdrawal syndrome in physically dependent patients. 6

Withdrawal symptoms include: 6

• Body aches, diarrhea, tachycardia, fever 6
• Runny nose, sneezing, piloerection, sweating 6
• Nausea/vomiting, nervousness, restlessness 6
• Abdominal cramps, weakness, increased blood pressure 6
• In neonates: convulsions, excessive crying, hyperactive reflexes 6

Management approach: Use the lowest effective naloxone dose to restore adequate respirations while minimizing withdrawal symptoms. 3, 6

Limitations of Naloxone

Naloxone is NOT effective against: 6

• Respiratory depression from non-opioid drugs 6
• Levopropoxyphene toxicity 6
• Partial agonists or mixed agonist/antagonists (buprenorphine, pentazocine) may show incomplete response or require higher naloxone doses—mechanical ventilation may be necessary 6

Additional Supportive Measures

• For severe bradycardia: Atropine administration 5
• For hypotension: Leg elevation and IV fluids 5
• For seizures: Benzodiazepines (diazepam) 5
• For extreme agitation: Diazepam or haloperidol if no respiratory depression risk 5