When Dean collapses after swallowing the pills, he falls onto his right side with his left arm (the one with his watch) outside his extended right arm - closest to the camera. When Michelle returns with the doctor, Dean's arm positions have changed: the left arm with his watch is closest to his chest and his extended right arm is closest to the camera. Since he's supposed to be unconscious, his arms shouldn't have moved.
Naloxone (Narcan) is an opioid antagonist, it is used to reverse an opioid overdose (heroin, morphine, hydrocodone, oxycodone fentanyl). As Dean took barbiturates, it would be of no help to him.
A person with serious injuries like broken ribs, dehydration, and especially a gun shot wound to the abdomen as in Sam's case, would not be treated at an urgent care clinic, they don't have the equipment or the personnel to treat injuries like those. It's possible that an isolated rural community might treat severe dehydration or broken ribs at an urgent care clinic if they were a long distance from a hospital, but they definitely would not be able to treat a gunshot wound, Sam would have been stabilized at the urgent care clinic then taken to the nearest emergency room.
When the doctor is examining Dean when he wakes up, she shines a light in his eyes to check for a concussion and says he has a pretty severe concussion. Not only does Dean react to the light, his pupils are not dilated, indicating that he does not, in fact, have a concussion.
Barbiturates would be a poor choice of drug to use to intentionally cause a fatal overdose if one planned to be resuscitated. There is no antidote for barbiturates, the only way an overdose can be treated is by removing any drug that hasn't been metabolized yet (stomach pumping or activated charcoal) and placing the person on life support and treating the overdose symptoms and waiting until the drug is cleared from the system, which is a process that takes hours or days (depending on the specific drug used and dosage), to complete. This is something Dean should know since him and Sam have a working knowledge of pharmacology due to their line of work. An intravenous opiate like morphine, hydromorphone (Dilaudid) or fentanyl would have been the best choice to accomplish what Dean wants. It would take effect much faster than taking oral barbiturates (2-3 minutes with IV opiates versus 20-30 minutes with oral barbiturates), and they wouldn't need to pump his stomach, all it would take to reverse an opiate overdose would be an injection of an opioid antagonist like naloxone (Narcan), and the opiate would be cleared from his system in less than a minute.
At 5:59 Sam and Dean are looking at a poster of four missing hikers. The header on the poster says "For" missing hikers.