Naloxone
naloxone injection
Pronunciation: nal-OX-oen
What it isCompetitive mu-opioid antagonist; emergency reversal of opioid-induced respiratory depression.
Why this oneIntranasal access lets a bystander reverse respiratory depression before clinicians arrive.
What limits itIts effect can wear off before the opioid, so recurrent sedation needs observation and redosing; dependent patients develop abrupt withdrawal.
FDA-approved for
- opioid overdose reversal (1971)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Opioid overdose, known/suspected (complete/partial reversal of opioid depression; also diagnostic) | Adults | 0.4-2 mg IV; repeat q2-3 min PRN | Titrate to adequate ventilation/alertness | 10 mg (if no response, question opioid diagnosis) |
| Postoperative opioid depression (partial reversal) | Adults | 0.1-0.2 mg IV q2-3 min to desired reversal | Repeat PRN at 1-2 h intervals; supplemental IM doses last longer | Titrate — excess reverses analgesia, raises BP |
| Opioid overdose, known/suspected | Pediatric | 0.01 mg/kg IV; if inadequate, 0.1 mg/kg (IM/SC in divided doses if no IV) | Titrate to response | Undefined |
| Postoperative opioid depression | Pediatric | 0.005-0.01 mg IV q2-3 min to desired reversal | Titrate to response | Undefined |
| Opioid-induced depression | Neonates | 0.01 mg/kg IV/IM/SC; may repeat per postoperative guidelines | Titrate to response | Undefined |
| Septic shock (adjunct to raise BP) | Adults | Optimal dose/duration not established | Undefined | Undefined |
Renal Not established; use with caution
Hepatic Not established; use with caution
If no response after 10 mg cumulative, question opioid-induced toxicity
Instructions
- IV route preferred in emergencies (fastest onset); IM/SC if IV unavailable
- May dilute for IV infusion in 0.9% NaCl or D5W (2 mg/500 mL = 0.004 mg/mL); titrate rate to response; discard after 24 h
- Do not mix with bisulfite/metabisulfite, long-chain or high-MW anions, or alkaline-pH solutions
- Keep patient under continued surveillance; repeat doses PRN — opioid duration may exceed naloxone's
Available strengths
- inj 0.4, 1 mg/mL
- sol 5 mg/0.5 mL
- inhaler 4 mg/.1 mL
- nasal spray 3, 4, 8, 10 mg/spray
Cautions
- Precipitates acute opioid withdrawal in physically dependent patients (incl. neonates of dependent mothers): body aches, diarrhea, tachycardia, fever, sweating, nausea/vomiting, irritability, increased BP; neonates also convulsions, excessive crying, hyperreflexia
- Recurrent respiratory/CNS depression: opioid duration may outlast naloxone — continued surveillance and repeat doses required
- Abrupt postoperative reversal: nausea, vomiting, sweating, tachycardia, hypertension, seizures, VT/VF, pulmonary edema, cardiac arrest (deaths reported); caution with pre-existing cardiac disease or cardiotoxic drugs
- Not effective against non-opioid respiratory depression; buprenorphine/pentazocine reversal may be incomplete — higher doses may be needed; mechanically assist ventilation if response incomplete
- Other resuscitative measures (airway, ventilation, cardiac massage, vasopressors) should be available
- Excess dosing in postoperative patients reverses analgesia and causes agitation
Adverse reactions
- Postoperative: hypotension, hypertension, VT/VF, dyspnea, pulmonary edema, cardiac arrest (death, coma, encephalopathy as sequelae)
- Abrupt reversal: nausea, vomiting, sweating, tachycardia, increased BP, tremulousness, seizures
- Acute opioid withdrawal syndrome in dependent patients
- Agitation, hallucination, paresthesia, injection-site reactions, flushing
Pregnancy No embryotoxicity/teratogenicity in animals; no adequate human studies — use only if clearly needed; may precipitate withdrawal in fetus and opioid-dependent mother; monitor hypertensive patients in labor
Lactation Unknown whether excreted in human milk; caution
Cost
| Strength | #/mo | generic $/unit | CostPlus | |
|---|---|---|---|---|
| 0.4 mg/mL | inj | per unit | $3.82/mL | not offered |
| 1 mg/mL | inj | per unit | $12.74/mL | not offered |
Other forms: Naloxone nasal spray (NARCAN)
Available combined with: Buprenorphine/ naloxone (SUBOXONE)
Generic entry1986
NO BOXED WARNINGS
Principal riskPrecipitated withdrawal in the opioid-dependent
Classes and tags
Clinical profile
Legacy pregnancy categoryB
Defining liabilityUsually well tolerated; abrupt opioid withdrawal can cause severe agitation, vomiting, hypertension and pulmonary complications.
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