Naloxone

Naloxone
This episode of Cracking Addiction continues the theme of harm reduction by discussing Naloxone in detail.

Naloxone is often used to treat opioid overdose with a major indication for usage being hypoventilation or a respiratory rate less than 8 breaths per minute. Naloxone is a mu and delta receptor antagonist with a half-life between 30 to 81 minutes which is shorter than most opioids. It is possible that repeated doses and/or infusions may be needed.
 
Potential side effects of naloxone include pulmonary oedema and seizures.
Patients and relatives can be trained to use Naloxone and it is effective in reducing deaths due to opioid overdose.

Naloxone is available as a vial, a prefilled syringe, or as a nasal spray. The usual dose of administration of naloxone is 400mcg.
The naloxone ampoule contains 400 micrograms, and a 3 mL syringe and a 23 g needle are needed to facilitate administration.
The naloxone prefilled syringe contains 2 mg (five 400 microgram doses in a single-use syringe).

The naloxone intranasal spray contains 1.8mg naloxone (as 2.2mg naloxone hydrochloride dihydrate) in a concentrated 0.1mL solution.
The initial dose of Naloxone intranasal spray is one spray into a nostril. It can be re-administered using a new container, into the other nostril after 2 to 3 minutes if the patient does not respond or responds and then relapses into respiratory depression. Further doses may be given every 2 to 3 minutes if needed until further assistance is available.

People who are given naloxone should be monitored for another two hours after the last dose of naloxone is given to make sure breathing does not slow or stop. Higher doses are occasionally necessary in overdoses of fentanyl and partial opioid agonists (eg buprenorphine). Failure to respond to 10mg usually indicates another cause of unconsciousness.
Author: Dr Thileepan Naren
MBBS FACRRM FRACGP
Thileepan is an Addiction Medicine Advanced Trainee and experienced general practitioner with a demonstrated history of working with disadvantaged and marginalized groups.