Opioid, sedative and recreational-drug toxicity — formative SAQs

1. Toxidrome and the first 60 seconds

This is the opioid toxidrome: pinpoint pupils, slow shallow breathing and reduced conscious level from mu-receptor agonism in the medullary respiratory centre. The first 60 seconds are an ABCDE primary survey: declare the concern, call the senior paediatric and resuscitation teams and the Poisons Information Centre, open and protect the airway, give high-flow oxygen, and start bag-mask ventilation because breathing is inadequate. Stabilisation precedes the antidote. ^{[1] [2]}

2. Naloxone strategy and doses

Naloxone is titrated to effective ventilation, not to full wakefulness, because over-reversal precipitates acute opioid withdrawal, vomiting, aspiration and rarely pulmonary oedema, while the goal is simply to restore adequate breathing. A reasonable initial dose is 10 micrograms per kilogram by the intravenous, intraosseous or intramuscular route, repeated every two to three minutes until ventilation is effective. In the apnoeic or severely depressed child, a larger dose of up to 100 micrograms per kilogram per dose is used, to a maximum of 2 mg per dose. Intranasal naloxone is a feasible alternative route when access is delayed. ^[2]

3. Infusion and prolonged observation

Sustained-release morphine is a long-acting opioid, and naloxone has a short half-life of roughly 60 to 90 minutes, shorter than the opioid. The child will recur as the naloxone wears off, and recurrence is the rule rather than the exception with long-acting agents. After the effective bolus dose is found, I start a naloxone infusion at about two-thirds of that effective dose per hour, titrated to keep ventilation adequate, and I observe for many hours to cover the duration of action of the opioid. ^[2]

4. Reassessment endpoints and escalation

After every action I return to airway, breathing, circulation, glucose and conscious level, and I judge the trend against the response I predicted. The endpoints are a safe airway, an effective respiratory rate and depth, an adequate saturation, a normal glucose and an improving conscious level — ventilation, not full wakefulness. I call retrieval and intensive care in parallel with resuscitation, before local support is exceeded, because the child will need prolonged observation and infusion management that may exceed a general ward or rural setting. ^[2]