What is the initial IV dose range for naloxone?

• A. 0.4-2 mg IV
• B. 2-4 mg IV
• C. 5-10 mg IV
• D. 0.1-0.2 mg IV

Answer: (A)

Naloxone reverses opioid effects by rapidly competing for mu receptors, and giving it IV produces a quick reversal of respiratory depression. Because you want to restore breathing without overshooting and causing withdrawal or agitation, dosing is started low and titrated to the patient’s response. A common starting IV bolus is 0.4 mg; if there’s not enough effect, you administer another 0.4 mg every 2–3 minutes, with a typical total dose around 2 mg. This makes 0.4–2 mg the appropriate initial range. Doses much smaller, like 0.1–0.2 mg, may be too weak to reverse the symptoms promptly, while starting with 2–4 mg or more initially can risk adverse effects and unnecessary escalation.