Medication guide
Naloxone dosing.
Reverse the respiratory depression — not the whole patient.
Adult dosing by route
| Route | Dose | Onset |
|---|---|---|
| IN | 4 mg (2 mg per nostril) | 2–5 min |
| IM | 0.4–2 mg | 2–5 min |
| IV/IO | 0.04–0.4 mg titrated | 1–2 min |
| Nebulized | 2 mg in 3 mL NS | 5 min |
Repeat every 2–3 min until respirations are adequate. Max ~10 mg — if no response, reconsider the diagnosis.
Pediatric
- < 5 yr or < 20 kg: 0.1 mg/kg IV/IO/IM/IN.
- ≥ 5 yr or ≥ 20 kg: 2 mg IV/IO/IM/IN.
Fentanyl-era considerations
- Fentanyl analogs may need multiple doses — don't quit at 4 mg IN.
- Duration of naloxone (30–90 min) < duration of many opioids — monitor for re-sedation.
- All overdose patients need transport even if fully reversed.
Precipitated withdrawal
Signs: agitation, vomiting, diaphoresis, hypertension, tachycardia. Rare but serious: pulmonary edema. Titrate slowly — you're supporting the airway, not "waking them up."
Frequently asked
- What is the standard naloxone dose?
- 0.4–2 mg IV/IM/IN, titrate to adequate ventilation. Start low (0.04–0.1 mg IV) in known opioid-dependent patients to avoid abrupt withdrawal.
- Is IN naloxone as effective as IV?
- Onset is slightly slower (2–5 min IN vs 1–2 min IV), but bioavailability is high and IN avoids needlestick risk. Standard IN dose is 4 mg/0.1 mL.
- How often can I repeat naloxone?
- Every 2–3 minutes until ventilation is adequate. Some opioids (fentanyl, methadone) outlast naloxone's 30–90 min duration — expect re-sedation.
- Should I fully reverse the patient?
- No. Titrate to respirations ≥ 10–12/min and adequate tidal volume. Full arousal often triggers combative withdrawal, vomiting, and pulmonary edema.
Drill toxicology questions
Free practice test →Educational use only. Follow local protocols and medical direction.