. Nitrous Oxide , otherwise known as "NOS" or happy/laughing gas. Overdose Main article: Opioid overdose Signs and symptoms of narcotic/opioid overdose include the following: euphoria , arousable somnolence (" nodding "), nausea , pinpoint pupils (except with Pethidine/Meperidine [ Demerol ]), hypoxia , or in combination with other types of