T40.416Underdosing of fentanyl or fentanyl analogs

T40.416 is the ICD-10-CM diagnosis code for underdosing of fentanyl or fentanyl analogs. It belongs to category T40 (poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]), block T36-T50 (poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.

Within T40.41 (poisoning by, adverse effect of and underdosing of fentanyl or fentanyl analogs), T40.416 is specifically for underdosing of fentanyl or fentanyl analogs. Related codes cover poisoning by fentanyl or fentanyl analogs, accidental (unintentional) (T40.411), poisoning by fentanyl or fentanyl analogs, intentional self-harm (T40.412), poisoning by fentanyl or fentanyl analogs, assault (T40.413), poisoning by fentanyl or fentanyl analogs, undetermined (T40.414) and adverse effect of fentanyl or fentanyl analogs (T40.415).

Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.

It was added in FY2021, effective October 1, 2020.