ICD-10-CM > S00-T88 > T36-T50 > T40 > T40.4 > T40.49 > T40.491 T40.491 Poisoning by other synthetic narcotics, accidental (unintentional) Non-Billable/Non-Specific Applicable To Poisoning by other synthetic narcotics NOS Codes T40.491A..., initial encounterT40.491D..., subsequent encounterT40.491S..., sequela