Reversal Agent

Naloxone

Pure opioid antagonist · Narcan

Mechanism: Competitive μ-opioid receptor antagonist.

Calculate dose for your patient

Enter weight (kg or lb). Always verify before administration.

Patient weight

Computed weight

70.0 kg · 154.3 lb

Opioid reversal (titrate)

0.04 mg – 0.14 mg

= 0.09–0.35 mL (0.4 mg/mL)

Titrate 0.04 mg increments to restore RR without abolishing analgesia.

Weight is saved on this device for the next calculator you open.

Full dose calculator

Onset

1–2 min

Duration

30–60 min (less than most opioids — re-narcotization risk)

Metabolism

Hepatic glucuronidation.

Dosing

Adult

Reversal: 0.04–0.4 mg IV q2–3 min. Overdose: 0.4–2 mg IV/IM/IN.

Pediatric

0.01 mg/kg IV (up to 0.1 mg/kg).

Indications

Opioid overdose / oversedation
Opioid-induced pruritus (low dose)

Contraindications

Known hypersensitivity

Side Effects

Acute withdrawal
Pulmonary edema (rare)
Pain crisis

Clinical Pearls

1Titrate in 0.04 mg increments to restore respiration without abolishing analgesia.

2Re-dose anticipated — duration is shorter than most opioids.

References & Further Reading

1
Textbook
Flood P, Rathmell JP, Shafer S. Stoelting's Pharmacology and Physiology in Anesthetic Practice. 5th ed. Philadelphia: Wolters Kluwer; 2015.
2
Textbook
Gropper MA, Miller RD, Cohen NH, et al., eds. Miller's Anesthesia. 9th ed. Philadelphia: Elsevier; 2020.
3
Textbook
Barash PG, Cullen BF, Stoelting RK, Cahalan MK, Stock MC, Ortega R, Sharar SR, Holt NF. Clinical Anesthesia. 8th ed. Philadelphia: Wolters Kluwer; 2017.
4
Textbook
Adriano A, Morris R, eds. 2021 CA-1 Tutorial Textbook (15th Ed.). Stanford University Medical Center, Department of Anesthesiology.

Citations are provided to direct further study. Always check the most current edition of guidelines and society recommendations — the information in this chapter is a teaching summary, not primary source material.