Naloxone Intravenous for Adults

Who can administer

May be administered by registered competent doctor or nurse/midwife

Important information

  • See Monitoring requirements - below
  • The duration of action of some opioids (including dextropropoxyphene, dihydrocodeine, methadone) may exceed that of naloxone. 
  • Doses used in acute opioid overdosage may not be appropriate for the management of opioid-induced respiratory depression and sedation in those receiving palliative care and in chronic opioid use

Available preparations

Naloxone 400 microgram per 1ml ampoule

Naloxone 400 microgram per 1ml minijet


Already in solution

Draw up using a 5 micron filter needle

Infusion fluids

Sodium chloride 0.9% or Glucose 5%

Methods of intravenous administration

Bolus intravenous injection (usual route)

  • Administer undiluted, inject over a few seconds (ref 3)

Continuous intravenous infusion (used in opioid overdose) (administer using an electronically controlled infusion device)

  • Add 2,000 micrograms (2mg) to 500ml infusion fluid (4micrograms per ml)
  • Alternative dilution: add 10,000 micrograms (10mg) to 50ml infusion fluid (200micrograms/ml) (unlicensed concentration) (ref 1)
  • Titrate to response
  • Initial rate may be set at 60% of initial intravenous bolus injection dose (in microgram/hour, see example under "Dose") (ref 2)

Intermittent intravenous infusion (post-operative use)

  • Add 2000 micrograms (2mg) to 500ml of infusion solution
  • This gives a concentration of 4 microgram/ml
  • See under continuous intravenous infusion for dose and rate adjustment

Dose in adults

1: Opioid overdose (known or suspected) Initial dose

  • Give 400 micrograms by bolus intravenous injection; if no response after 1 minute, give 800 micrograms, and if still no response after another 1 minute, repeat dose of 800 micrograms. If still no response, give 2mg (4mg may be required in a seriously poisoned patient), then review diagnosis. Further doses may be required if respiratory function deteriorates (ref 2)
  • If no response is observed after 10mg of naloxone has been administered, the diagnosis of opioid or partial-opioid induced toxicity should be questioned
  • In some circumstances (see under Important information) it may be necessary to use a continuous intravenous infusion (see above for suitable dilutions) 
    • Consider an initial rate over 1 hour, equal to 60% of the initial intravenous injection (ref 2)
    • For example, if 400microgram stat dose given, consider an initial rate for this infusion of 240 micrograms per hour for the first hour and titrate to response.

2: Post-operative use (To reverse central depression resulting from the use of opioids during surgery)

  • Give 100 to 200 micrograms (approx. 1.5 to 3 micrograms/kg), as a bolus intravenous injection
  • If response inadequate, increments of 100 micrograms may be given every two minutes to obtain optimum respiratory response while maintaining adequate analgesia
  • Alternatively, subsequent doses may be given by intramuscular injection every one to two hours 

3: Severe itch or vomiting due to intrathecal or epidural morphine     

Severe itch or vomiting due to PCA opiate, when standard antiemetics and antipruritics have failed (ref 4,5)

  • Give 40 micrograms intravenously 
  • Repeat every 20 minutes
  • Use as needed until the analgesia/opiate regimen has been reviewed by the pain team or anaesthetist


  • The duration of action of some opioids (including dextropropoxyphene, dihydrocodeine, methadone) may exceed that of naloxone. In these circumstances, an intravenous infusion of naloxone will provide sustained antagonism of the opioid without the need for repeated injections
  • Patients should be monitored to ensure respiratory depression does not recur
  • Further doses may be necessary in this situation

Further information

  • Naloxone is not effective against respiratory depression caused by non-opioid drugs
  • Reversal of buprenorphine-induced respiratory depression may be incomplete
  • If IV administration is impractical, naloxone may be administered by the IM or SC route, although onset of action may be slower (ref 2)


  • Store below 25°C


SPC Naloxone hydrochloride injection USP 400 micrograms/ml Mercury, Feb 2013

(1)Injectable Medicines Guide Medusa, accessed online 11/9/2018

(2) BNF 74

(3) Injectable Medicines Administration Guide UCL Hospitals 3rd Ed

(4)  Dr Olivia Finnerty, consultant anaesthetist.  Expert opinion.  December 10th, 2019

(5) King Edward Memorial Hospital, Western Australia Adult medication monograph September 2017

Therapeutic classification

Opioid antagonists