The answer is B, IM naloxone. Naloxone (Narcan) is an opioid receptor antagonist used in the treatment of opioid overdose. Naloxone works by displacing opioids at the receptor and blocking the effects. It is indicated when there are signs of unknown central nervous system depressant overdose, particularly when there is respiratory depression. The risks of benefits of naloxone delivery in these patients far outweigh the risks. Given this patient’s sensorium, low respiratory rate, and constricted pupils, this likely represents an opioid overdose. The opioid epidemic has led to a massive increase in overdoses; naloxone rescue kits are now available in some places over-the-counter. There are several formulations, with intramuscular injection (either vial + syringe or autoinjector) being the most common. A, CPR is not necessary as the patient has a pulse. C, buprenorphine is an opioid receptor partial agonist used in the treatment of opioid use disorder. D, Naltrexone, like naloxone, is an opioid receptor antagonist. However, it has a longer mechanism of action and is used in alcohol use disorder to prevent cravings and in opioid use disorder to prevent cravings and diminish the effects of opioids if ingested. It is not used in overdoses. NalOxone → O for overdose. NalTRExone → LTRE for long term treatment.

Publication reference : Kerensky T, Walley AY. Opioid overdose prevention and naloxone rescue kits: what we know and what we don’t know. Addiction Science & Clinical Practice. 2017;12:4. doi:10.1186/s13722-016-0068-3.
Reference URL: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5219773/