Opioid and sedative poisoning

Manage now— do this, in order

• Ventilation is the treatment; the antidote is a convenience — protection of the airway and assisted ventilation are the most important treatment measures for any poisoned patient, and they precede the antidote. Establish a patent airway by positioning, suction and insertion of a nasopharyngeal or oropharyngeal airway, and nurse the unintubated patient in the lateral (recovery) position with suction available.
• Assist with a bag-valve-mask device or mechanical ventilator: assisted ventilation at 10–12 breaths per minute in an adult is the single highest-value intervention here — support the airway, ventilate, give naloxone and re-decide at three minutes. Intubate if the patient is deeply comatose or airway reflexes are depressed — but these airway interventions may not be necessary if the patient is intoxicated by an opioid and responds to intravenous naloxone.Doctor / NurseNot available at your setup — Mechanical ventilator, Endotracheal intubation kit. Where no ventilator is available, ventilate by bag-valve-mask at 10–12 breaths per minute while naloxone takes effect.
• Naloxone, adult, illicit or unknown opioid, apnoeic or barely breathing: 0.4–2 mg intravenously, or the same dose intramuscularly or by endotracheal tube, or 2–4 mg by intranasal spray; repeat every 2–3 minutes, escalating — up to 5–10 mg may be required for potent opioids, and total doses of 10 mg or greater may be needed for fentanyl or buprenorphine. Adult breathing but inadequately: 0.4 mg intravenously repeated every 2–3 minutes, titrated (chart).Doctor / Nurse
• Naloxone in prescribed-opioid, palliative or post-operative over-sedation or a known chronic user: a tester dose of 0.04 mg intravenously, taken from naloxone 0.4 mg diluted to 10 mL with 0.9% sodium chloride (0.04 mg/mL), repeated every 1–2 minutes and titrated to respiratory rate — this reverses respiratory depression without entirely reversing analgesia. Child: 0.01 mg/kg intravenously, intramuscularly or intraosseously; if inadequate, 0.1 mg/kg (usual maximum 2 mg per dose), repeated as needed. Never give naloxone to the neonate of an opioid-using or opioid-treated mother — it may precipitate severe withdrawal and seizures; support the airway and ventilate instead. Where re-sedation is expected, give repeated boluses at the effective dose, or a continuous infusion at approximately two-thirds of the effective bolus dose per hour, titrated hourly against the respiratory rate.Doctor / NurseNot available at your setup — Infusion pump.
• The endpoint is a respiratory rate of about 12 or more with adequate depth, a maintained saturation without assistance, and return of airway-protective reflexes — not a fully alert patient; a rousable but drowsy patient who is breathing well and swallowing their own saliva is a success. Never titrate the antidote to consciousness — titrate to respiration, because over-reversal produces acute withdrawal with agitation, vomiting into an unprotected airway, aspiration, and a patient who self-discharges into the circumstances that nearly killed them. Never keep escalating past a cumulative 10 mg with no respiratory response — failure to respond to 10 mg is information, not a reason for more naloxone: consider a non-opioid cause, a mixed overdose, hypoxic brain injury, a structural intracranial cause, or buprenorphine, and ventilate.
• Remove every transdermal opioid patch and wash the skin beneath it — a patch left in place keeps releasing drug for hours after the naloxone has worn off, and re-sedation after the antidote wears off is the commonest mechanism of a death occurring after apparently successful treatment.
• Give 50% dextrose 50–100 mL by intravenous bolus to all obtunded, comatose or convulsing patients unless a rapid point-of-care glucose test rules out hypoglycaemia; in children 10% dextrose 2–5 mL/kg intravenously. Thiamine 100 mg intramuscularly before the dextrose, or in the intravenous fluids, in patients with alcohol use disorder or malnourishment who may have marginal thiamine stores.Doctor / Nurse
• Hypotension: repeated 200 mL intravenous boluses of 0.9% sodium chloride or other isotonic crystalloid up to a total of 1–2 litres (paediatric 10–20 mL/kg per bolus); if fluid therapy is unsuccessful after adequate volume replacement, give vasopressors by intravenous infusion — noradrenaline first; and remember hypothermia may itself be the cause of refractory hypotension, so rewarm gradually unless the patient is in cardiac arrest. Seizures: lorazepam 2–3 mg intravenously, or diazepam 5–10 mg intravenously, or midazolam 5–10 mg intramuscularly if intravenous access is not immediately available (paediatric lorazepam 0.1 mg/kg to a maximum 4 mg, diazepam 0.1–0.3 mg/kg to a maximum 10 mg, or midazolam 0.1 mg/kg IV or 0.2 mg/kg buccally); if convulsions continue, phenobarbital 15–20 mg/kg slowly intravenously over no less than 30 minutes — for drug-induced seizures phenobarbital is the preferred agent. A wide QRS from co-ingested sodium-channel blockade: sodium bicarbonate 50–100 mEq by intravenous bolus. Torsades de pointes: magnesium 2 g intravenously over 2 minutes.Doctor / Nurse
• Activated charcoal for small or moderate ingestions: 50–100 g orally or by gastric tube as an aqueous slurry in an adult, 1 g/kg (maximum 50 g) in a child — but not to a comatose or convulsing patient unless the airway is first protected by a cuffed endotracheal tube, and never at the cost of delaying ventilation or naloxone; whole-bowel irrigation with polyethylene glycol (adult 1–2 L/hour, child 25 mL/kg/hour) is indicated for body packers and large modified-release ingestions. Continuous observation for at least 3–4 hours after the last naloxone dose is mandatory; some authorities specify at least 6 hours, and the longer figure is safer — and features of opioid poisoning can be prolonged for up to 48 hours after methadone or oxycodone, so those agents, with modified-release morphine, transdermal fentanyl and buprenorphine, warrant at least 24 hours of monitored observation. Flumazenil should rarely be given, and the safe management of sedative poisoning is airway, oxygen, assisted ventilation, fluids, warmth and time.