Naloxone bolus regimen
Naloxone bolus doses are preferably administered intravenously; however, they can be given intramuscularly or intranasally if intravenous access cannot be easily established. Support of airway and breathing is the priority to prevent hypoxia while waiting for naloxone to take effect.
The following regimens are indicated for all opioid poisonings, other than buprenorphine poisoning. If a naloxone bolus regimen is required for buprenorphine poisoning, see Buprenorphine poisoning.
For adults with hypoventilation due to opioid poisoning, use:
naloxone 0.04 to 0.2 mg intravenously, every 2 to 3 minutes according to clinical effect, up to a total initial dose of 2 mg1. Aim for a respiratory rate of greater than 10 breaths per minute and oxygen saturation greater than 92% on room air. naloxone
For children with hypoventilation due to opioid poisoning, use:
naloxone 0.01 mg/kg up to 0.2 mg intravenously, every 2 to 3 minutes according to clinical effect, up to a total initial dose of 2 mg1. Aim for a normal age-appropriate respiratory rate and oxygen saturation greater than 92% on room air2. naloxone
For opioid poisoning, if intravenous access is not easily established, for adults and children, initially use:
1naloxone 0.4 to 2 mg (depending on the preparation and local protocols), intramuscularly3. A dose of 0.8 mg is the most appropriate to achieve adequate respiration and avoid the need for repeat doses naloxone
OR
1naloxone 1.8 mg/0.1 mL nasal spray, 1 spray (1.8 mg) into one nostril4.Krieter 2018 naloxone
If there is a significant delay to intravenous access and the patient is still hypoventilating, a second dose of intramuscular or intranasal naloxone (using a new nasal spray into the other nostril) after 2 to 3 minutes may be beneficial.
Adequate reversal of opioid toxicity is indicated by:
- increased respiratory drive—normal respiratory rate and oxygen saturation greater than 92% on room air
- improved level of consciousness sufficient for the patient to maintain their airway (ie mildly sedated but easily roused).
A total intravenous bolus dose of up to 2 mg of naloxone is usually sufficient to reverse toxicity and inadequate response to this dose suggests other causes of toxicity (eg co-ingestants). Poisoning due to synthetic opioids (eg fentanyl analogues) may require larger doses of naloxone. If there is inadequate response following a total intravenous bolus dose of up to 2 mg of naloxone, consult a clinical toxicologist or poisons information centre about whether to give further doses (up to a total bolus dose of 10 mg) or intubate and ventilate the patient. Intubation and ventilation is generally more practical than administering large doses of naloxone5.
If toxicity recurs after initial response to the naloxone bolus, repeat the naloxone bolus regimen. If the patient responds to a further titrated naloxone bolus, consider starting a naloxone infusion to prevent further recurrence of toxicity.
If naloxone supplies are insufficient, intubate and ventilate the patient.