Naloxone

Question 1

Naloxone Mechanism of Action

Answer 1

• Naloxone is an opiate receptor antagonist (blocker). By blocking opiate receptors naloxone reverses the effects of opiates, particularly respiratory
depression and sedation.

Question 2

Naloxone Indications

Answer 2

Opiate poisoning is suspected and the patient has a significantly impaired level of consciousness or significantly impaired breathing.
Excess adverse effects from administration of opiates.

Question 3

Naloxone Contraindications

Answer 3

Known severe allergy.

Question 4

Naloxone Cautions

Answer 4

Chronic opiate use. If the patient is taking an opiate chronically, there is a risk of adverse physiological effects associated with rapid opiate withdrawal.

Question 5

Naloxone Use during pregnancy/breastfeeding

Answer 5

• Safety has not been demonstrated in pregnancy, but naloxone should be administered if indicated.
• May be administered if the patient is breastfeeding. Advise the patient to stop breastfeeding and seek further advice from their lead maternity carer or GP.

Question 6

Naloxone Dosing

Answer 6

• 0.1-0.4 mg IV every five minutes as required for an adult.
• 0.8 mg IM as required for an adult. This may be repeated every 20 minutes.
• See the paediatric drug dose tables for a child.

Question 7

Naloxone IV Administration

Answer 7

• The preferred route for administration is IV.
• IV: dilute 0.4 mg to a total of 4 ml. This final solution contains 0.1 mg/ml.
• Administer the minimum dose required to produce improvement. Rapid
reversal of opiates may be associated with seizures, hypertension, pulmonary oedema or severe agitation, particularly if the patient takes opiates regularly.

Question 8

Naloxone IM Administration

Answer 8

• IM: administer undiluted. The preferred site is the lateral thigh as this has the
best absorption. If this site is not suitable use the lateral upper arm.

Question 9

Naloxone Rapid reversal complications

Answer 9

Seizures
Hypertension
Pulmonary oedema
Severe agitation

Question 10

Naloxone Common adverse effects

Answer 10

• Sweating.
• Tachycardia.
• Hypertension.

Question 11

Naloxone Onset of action

Answer 11

• IV: 1-2 minutes.

* IM: 5-10 minutes.

Question 12

Naloxone Duration of action

Answer 12

• 30-60 minutes.
• The duration of action of naloxone may be shorter than the duration of action
of the opiate that has been administered/taken and naloxone may need to be
repeated.

Question 13

Naloxone Preparation

Answer 13

0.4mg/1ml ampoule

Question 14

Naloxone Pharmacokinetics

Answer 14

• Naloxone is predominantly metabolised by the liver.

* There are no significant effects from liver impairment on acute administration.

Question 15

Naloxone Common interactions

Answer 15

None

Question 16

Naloxone in Cardiac arrest

Answer 16

Nil role in cardiac arrest - CA due to respiratory arrest, run as secondary arrest
If ROSC occurs still no role due to risk of:
Seizures
Hypertension
Pulmonary oedema
Severe agitation