Synopsis
Recognise opioid sedation, respiratory depression and neurotoxicity early, distinguish them from disease deterioration, provide proportionate emergency reversal, treat precipitating illness and redesign analgesia safely when renal clearance is reduced.
- Increasing sedation, impaired attention and slowed breathing are more important toxicity signals than pinpoint pupils alone.
- First-line emergency care is airway and ventilation support plus stopping further opioid; naloxone supplements rather than replaces resuscitation.
- In opioid-dependent palliative patients, titrate naloxone to adequate breathing when possible because complete abrupt reversal can cause severe pain and withdrawal.
- Observe beyond the antagonist's action and anticipate repeat doses or infusion for modified-release, patch, methadone or renally accumulated exposure.
- Check the last 72 hours of regular, rescue, patch and pump doses, all recent conversions, renal trend, hydration and concurrent sedatives.
- Morphine, diamorphine and codeine rely on renal elimination of active metabolites and are commonly avoided or used only with expert adjustment in severe renal impairment.
- Fentanyl and alfentanil have no clinically important active renally cleared metabolites, but potency, route and conversion still require specialist or pharmacy governance.
- Oxycodone can also accumulate in renal dysfunction and is not a risk-free default; use reduced dosing and close review only under the relevant formulary.
- The gold-standard recovery plan treats the precipitant, reduces or rotates the opioid, recalculates rescue, cancels old prescriptions and monitors through both drugs' pharmacological tails.
Key red flags
Progressive drowsiness usually precedes major respiratory depression and must not be dismissed as normal sleep after a dose increase.
Respiratory rate below 8, cyanosis, apnoea, inability to rouse or carbon-dioxide retention needs airway support and proportionate naloxone.
New myoclonus, hallucinations, delirium, allodynia or diffuse hyperalgesia indicates opioid neurotoxicity, often before severe respiratory signs.
Acute kidney injury, eGFR below 30 mL/min/1.73 m², dehydration or sepsis can rapidly turn a previously tolerated morphine regimen toxic.
Multiple patches, an infusion-programming error, recent conversion or concurrent benzodiazepine, gabapentinoid or alcohol exposure demands immediate dose reconstruction.
Reduced consciousness at end of life may have several causes; naloxone is for clinically important opioid respiratory depression, not routine reversal of expected dying.
A response to naloxone does not exclude intracranial disease, sepsis, hypoglycaemia or mixed toxicity and does not end observation.
Slow shallow ventilation, difficult rousing, cyanosis or hypercapnia with compatible exposure is a life-threatening opioid pattern.
Investigation priorities
Measure arousability, respiratory rate and depth, airway, oxygenation, circulation, temperature, pupils and capillary glucose.
Management branches
The patient is difficult to rouse and has clinically important hypoventilation after possible opioid exposure.
- Stop opioid, call emergency help, support airway and ventilation, give oxygen as indicated, check glucose and attach appropriate continuous monitoring.
- Give intravenous naloxone under the local emergency protocol, titrating to adequate ventilation when opioid dependence permits and escalating doses for apnoea or severe overdose as directed.
- Observe for recurrent depression, repeat or infuse naloxone if necessary and investigate long-acting exposure, renal accumulation and mixed causes.