Final answer:
The man likely overdosed on Morphine, given the symptoms of opioid overdose such as unresponsiveness, cyanosis, and pinpoint pupils. Naloxone is the emergency antidote used to reverse the effects of opioid overdoses.
Step-by-step explanation:
A man had a repair of his leg fracture and was found unresponsive, cold, blue fingernails, with pinpoint pupils. The drug that he likely overdosed on is d) Morphine. These symptoms are indicative of opioid overdose. Opioids can depress the respiratory system, leading to slowed or stopped breathing, resulting in unresponsiveness and blue discoloration due to lack of oxygen (cyanosis). Pinpoint pupils are another hallmark of opioid overdose. Naloxone (Narcan) is a medication used as an emergency treatment for opioid overdose, which can reverse the effects and prevent death by keeping the person breathing until further medical assistance is available.