Opiod Toxicity Flashcards
What are features of opiate toxicity?
- Decreased GCS
- Respiratory depression
- Constipation/decreased bowel sounds
- Bradycardia/hypotension
- Hypothermia
- Seizures
- Bilateral miosis
- Euphoria/dysphoria
Which of the 3 main opioid receptors is most implicated in the development of respiratory depression in overdose?
u-receptor and δ-receptor agonism
What is not a reliable sign of opiate intoxication?
Pinpoint pupils - variable presentation in opioid overdose
How does renal dyfunction influence opioid toxicity?
Interferes with excretion, therefore certain opioids accumulate more easily
Which opioids/opiates are more likely to accumulate in renal dyfunction?
- Morphine
- Diamorphine
- Codeine
- Pethidine
Which opiates are better to use in renal dyfunction?
- Oxycodone
- Fentanyl
- Alfentanyl
Why can some opioids cause itch?
Due to histamine release - particularly with codeine
How would you manage someone with suspected opioid toxicity?
- Airway maneuvre - head tilt chin lift
- Ventilate
- Consider need for ABG
- IV/IM naloxone
- Look for sources of exogenous opioids
- Management of complications
- Benzodiazepines - seizures/agitation/delerium
- Chlorphenamine - pruritis
What clinical circumstances do you need to take into account when considering naloxone regime to give?
Whether the patient is acute opioid intoxication or whether they are on opioids for pain relief post-op/palliatively - determines the rate of titration of naloxone
How would you administer naloxone when treating opioid toxicity int the acutre rescuscitative phase?
- Give 400 mcg initially
- If no response after 60 seconds, give 800 mcg
- If still no response after 60 seconds, give further 800 mcg
- If still no response after 2mg overall, give further 2 mg (large doses may be required for severely intoxicated individuals
- Aim for reversal of respiratory depression, not full reversal of unconsciousness
What would failure to respond to rescuscitative naloxone suggest?
Another CNS depressant or brain damage is present
What is important to remember about nalxone in terms of duration of action relative to that of opiates?
Shorter duration of action (1-1.5 hours), therefore narcosis may recur and multiple doses may be required
What is the duration of action of IV naloxone vs IM naloxone?
IV - 1-1.5 hours
IM - 3 hours
How long does it take naloxone to act IV vs IM
- IV - 1-2 minutes
- IM - 3-5 minutes
What are features of opioid withdrawal?
- Flu-like symptoms: rhinorrhea, chills, piloerection, myalgia, arthralgia, leg cramps
- GI complaints: nausea, vomiting, abdominal pain, diarrhea, hyperactive bowel sounds
- Features of sympathetic hyperactivity: mydriasis, tachycardia, hypertension, hyperreflexia
- Features of CNS stimulation: insomnia, yawning, irritability, anxiety, agitation, aggression
