Naloxone

Opioid Antagonist·Toxicology & Antidotes

Opioid overdose, reversal of intra-operative opioid sedation

PBSREVERSALPrenoxad (IM), Nyxoid (Intranasal)Ampoules (400 mcg/1 mL) for…S4+1

Max Dose

10 mg (STAT)

Half-life

1 h (Short!)

Resedation

HIGH RISK

Route

IV / IM / IN

Rapid Summary

Overview

Pure competitive mu-opioid receptor antagonist. Rapidly reverses opioid-induced respiratory depression and coma.

Maximum Dose

Titrated to effect. If 10 mg total is given with no response, the coma is NOT caused by opioids.

Clinical Focus

Has a much shorter half-life than most opioids. The patient WILL re-sedate and stop breathing an hour later. Must observe closely.

Bottom Line

Naloxone is the essential opioid antagonist for reversal of life-threatening respiratory depression, but has a shorter half-life than most opioids requiring repeated dosing and observation.

Formulation & Access

Brand Names

Prenoxad (IM), Nyxoid (Intranasal)

Parenteral

Ampoules (400 mcg/1 mL) for IV / IM / SC. Intranasal spray.

Prescribing & PBS

Pharmacy Medicine (S3) for take-home naloxone. Hospital supply for ampoules.

Indications & Use

Primary

PBSTGA

Opioid overdose, reversal of intra-operative opioid sedation.

Clinical Place

The definitive opioid antidote. Can be given by laypeople via nasal spray in the community.

Quick reference

Class & Role

Opioid Antagonist — Pure competitive mu-opioid receptor antagonist.

Route / Formulation

Ampoules (400 mcg/1 mL) for IV / IM / SC. Intranasal spray. (Prenoxad (IM), Nyxoid (Intranasal))

Usual Dose & Max

IV / IM 400 mcg STAT. Repeat every 2-3 mins until breathing returns. Titrated to effect. If 10 mg total is given with no response, the coma is NOT caused by opioids.

Key Indication Doses

Opioid Arrest / Apnoea: IV / IM 400 mcg STAT. Repeat every 2-3 mins until breathing returns. Iatrogenic Sedation (Ward): IV 20-40 mcg (Micro-dosing). Repeat every 2 mins. (Goal is to restore breathing without causing agonizing withdrawal pain). Community Overdose: Intranasal (Nyxoid) 1.8 mg spray into one nostril.

Best Uses

Naloxone is the essential opioid antagonist for reversal of life-threatening respiratory depression, but has a shorter half-life than most opioids requiring repeated dosing and observation.

Avoid / Cautions

NONE — No absolute contraindications in life-threatening respiratory depression.

Key Risks

Neurological: Acute, violent opioid withdrawal (agitation, aggression, vomiting, extreme pain, seizures). Cardiovascular: Tachycardia, severe hypertension, acute pulmonary oedema (from massive sympathetic surge upon waking).

Key Interactions

Buprenorphine (Suboxone). Buprenorphine binds so tightly to the receptor that standard doses of Naloxone cannot displace it. Massive doses (or continuous infusions) are required.

Monitoring

Continuous SpO2 and RR. The patient must be observed for at least 2-4 hours post-administration (or longer for sustained-release opioids) to catch re-sedation.

Clinical Pearl

Methadone lasts for 40 hours. Naloxone lasts for 1 hour. If you reverse a methadone overdose, you MUST set up a continuous IV Naloxone infusion (e.g., 2/3 of the wake-up dose per hour), or they will die when you turn your back.

Access

Prenoxad (IM), Nyxoid (Intranasal)

Brand: Prenoxad (IM), Nyxoid (Intranasal)

Naloxone

Opioid Antagonist·Toxicology & Antidotes

Opioid overdose, reversal of intra-operative opioid sedation

PBSREVERSALPrenoxad (IM), Nyxoid (Intranasal)Ampoules (400 mcg/1 mL) for…S4+1

Max Dose

10 mg (STAT)

Half-life

1 h (Short!)

Resedation

HIGH RISK

Route

IV / IM / IN

Rapid Summary

Overview

Pure competitive mu-opioid receptor antagonist. Rapidly reverses opioid-induced respiratory depression and coma.

Maximum Dose

Titrated to effect. If 10 mg total is given with no response, the coma is NOT caused by opioids.

Clinical Focus

Has a much shorter half-life than most opioids. The patient WILL re-sedate and stop breathing an hour later. Must observe closely.

Bottom Line

Naloxone is the essential opioid antagonist for reversal of life-threatening respiratory depression, but has a shorter half-life than most opioids requiring repeated dosing and observation.

Formulation & Access

Brand Names

Prenoxad (IM), Nyxoid (Intranasal)

Parenteral

Ampoules (400 mcg/1 mL) for IV / IM / SC. Intranasal spray.

Prescribing & PBS

Pharmacy Medicine (S3) for take-home naloxone. Hospital supply for ampoules.

Indications & Use

Primary

PBSTGA

Opioid overdose, reversal of intra-operative opioid sedation.

Clinical Place

The definitive opioid antidote. Can be given by laypeople via nasal spray in the community.

Quick reference

Class & Role

Opioid Antagonist — Pure competitive mu-opioid receptor antagonist.

Route / Formulation

Ampoules (400 mcg/1 mL) for IV / IM / SC. Intranasal spray. (Prenoxad (IM), Nyxoid (Intranasal))

Usual Dose & Max

IV / IM 400 mcg STAT. Repeat every 2-3 mins until breathing returns. Titrated to effect. If 10 mg total is given with no response, the coma is NOT caused by opioids.

Key Indication Doses

Best Uses

Naloxone is the essential opioid antagonist for reversal of life-threatening respiratory depression, but has a shorter half-life than most opioids requiring repeated dosing and observation.

Avoid / Cautions

NONE — No absolute contraindications in life-threatening respiratory depression.

Key Risks

Key Interactions

Buprenorphine (Suboxone). Buprenorphine binds so tightly to the receptor that standard doses of Naloxone cannot displace it. Massive doses (or continuous infusions) are required.

Monitoring

Continuous SpO2 and RR. The patient must be observed for at least 2-4 hours post-administration (or longer for sustained-release opioids) to catch re-sedation.

Clinical Pearl

Access

Prenoxad (IM), Nyxoid (Intranasal)

Brand: Prenoxad (IM), Nyxoid (Intranasal)