Naloxone dose of 0.4 mg is delivered by which route?

• A. IV
• B. IN
• C. Subcutaneous
• D. IM auto-injector

Answer: (D)

Naloxone is given at 0.4 mg most reliably when delivered intramuscularly using an auto-injector. This device is designed for quick, easy use in the field and provides a fixed 0.4 mg dose that can be administered without establishing IV access, making it ideal for prehospital BLS settings. Other routes exist, but they don’t align with the 0.4 mg dose example: intranasal doses are typically higher (around 2 mg per spray), and IV or subcutaneous delivery either isn’t as rapid to onset or isn’t the standard fixed-dose format in many EMS protocols. So the best match for delivering a 0.4 mg dose is the intramuscular auto-injector.