Opioid Toxicity causes:

1. Drowsiness
2. Respiratory Depression – Hypo-ventilation and decreased respiratory rate
3. Pupillary Miosis

Other Symptoms may include (but are not diagnostic or opioid toxicity):

• Nausea and vomiting
•  Neuropsychiatric features including nightmares, anxiety, agitation, euphoria, dysphoria,
  depression, paranoia and hallucinations
•  Urticaria and pruritis
•  Convulsions
•  Hypotension and bradycardia
•  Hypothermia secondary to environmental exposure

Naloxone is the antidote to Opioids however as these are commonly co-ingested with other depressants. full reversal of symptoms may not occur with treatment.

In acute opioid toxicity, the aim of naloxone administration should be reversal of respiratory depression and maintenance of airway protective reflexes, not full reversal of unconsciousness.

Opioid Toxicity Treatment

Naloxone infusion if required is based on the total dose given to obtain Respiratory rate of 10

Link to the full guidance is here