National Certified Addiction Counselor, Level I (NCAC I) Practice Exam 2025 – Comprehensive All-in-One Guide to Exam Success!

Naloxone is a common opioid antagonist, meaning it works to block the effects of opioids in the brain. It is primarily used in emergency situations to reverse opioid overdoses, as it can quickly restore normal respiration to a person who has stopped breathing due to opioid toxicity. Naloxone acts by competing for the same receptors in the brain as opioids, effectively displacing them and reversing their effects, which is crucial in life-threatening situations involving opioid overdose.

Other choices listed serve different purposes: Methadone is a long-acting opioid used for pain management and as part of a treatment program for opioid dependence. Dihydromorphine is an opioid analgesic with similar effects to morphine. MPTP is a neurotoxin that can cause symptoms similar to Parkinson's disease and is not related to opioid treatment or antagonism. Thus, Naloxone specifically fits the definition of an opioid antagonist, making it the correct answer.