Naloxone
Naloxone is a mu-receptor antagonist used in the treatment of opioid overdose; it may be required following opioid administration if the patient is difficult to rouse or is hypoventilating. Opioid overdose (poisoning) manifests as opioid-induced ventilatory impairment. Start appropriate resuscitation measures (eg support of airway and breathing) alongside administration of naloxone.
Opioid overdose associated with therapeutic use occurs on a spectrum—the dose of naloxone required depends on the context (eg clinical urgency) and intent (eg whether complete or partial opioid reversal is required). Smaller doses of naloxone are more commonly used for postoperative reversal of opioid sedation; larger doses are used for life-threatening opioid poisoning. If overdose with an opioid that has high affinity for the mu-receptor (eg buprenorphine) is suspected, larger naloxone doses may be required; for advice on buprenorphine overdose, see Buprenorphine poisoning. If the opioid poisoning is not associated with therapeutic use, see Opioid poisoning: general management.
Intravenous administration of naloxone has the fastest onset of action (approximately 1 minute), allowing rapid assessment of response, titration to effect and prompt initiation of intravenous infusion if required. If the intravenous route is not available, intranasal, subcutaneous or intramuscular administration may be used.
The duration of action of naloxone is relatively short (15 to 30 minutes) compared to that of opioids. Continuously observe the patient for indicators of opioid-induced ventilatory impairment because repeat administration or infusion of naloxone may be required.
Rapid, complete opioid reversal using large doses of naloxone can cause serious adverse effects (eg pulmonary oedema, cardiac arrhythmias), result in return of severe pain and precipitate withdrawal in opioid-tolerant patients. Small, incremental intravenous doses of naloxone are preferred unless the situation is urgent (eg medication administration error causing massive overdose, the patient has a significantly reduced conscious state or respiratory arrest). If smaller doses of naloxone are appropriate (eg for postoperative reversal of opioid sedation), use:
naloxone 40 to 100 micrograms (child less than 12 years:1 to 5 micrograms/kg up to 100 micrograms) intravenously every 2 minutes, if required, until the patient is more awake and breathing adequately. Start at the lower end of the dose range and titrate doses according to response to reduce the risk of pain or abrupt opioid withdrawal. Use ideal bodyweight in overweight children. opioid reversal naloxone
If the situation is urgent (ie the patient has a significantly depressed conscious state or respiratory arrest), higher doses of naloxone are required; use:
naloxone 100 to 200 micrograms (child less than 12 years: 10 micrograms/kg up to 200 micrograms) intravenously every 2 minutes, if required, until the patient is more awake and breathing adequately, up to an initial cumulative dose of 2 mg. Use the higher end of the dose range in life-threatening situations (eg respiratory arrest). Use ideal bodyweight in overweight children. naloxone
A total intravenous dose of up to 2 mg of naloxone is usually sufficient to reverse toxicity and inadequate response to this dose should prompt review of the diagnosis. If opioid toxicity is not adequately reversed after a total dose of 2 mg of naloxone (given by incremental doses), seek expert advice about whether to give further doses (up to a total bolus dose of 10 mg) or intubate and ventilate the patient.
If toxicity recurs after initial response to naloxone, give additional doses of naloxone until the patient is more awake and breathing adequately—use the regimen above. If the patient responds to repeat dosing, consider starting naloxone infusion to prevent further recurrence of toxicity. Seek expert advice.
If intravenous access is not immediately available in urgent situations, for adults and children, use:
1 naloxone 1.8 mg/0.1 mL nasal spray, 1 spray (1.8 mg) into one nostril1. Repeat doses may be given after 2 to 3 minutes, if required, until the patient is more awake and breathing adequately. Alternate nostrils between doses naloxone
OR
2 naloxone 400 micrograms intramuscularly or subcutaneously, every 5 minutes, if required, until the patient is more awake and breathing adequately. naloxone