T40.606Underdosing of unspecified narcotics

T40.606 is the ICD-10-CM diagnosis code for underdosing of unspecified narcotics. 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 T40.60, choose T40.606 (Underdosing of unspecified narcotics) only when documentation doesn't support a more specific option: poisoning by unspecified narcotics, accidental (unintentional) (T40.601), poisoning by unspecified narcotics, intentional self-harm (T40.602), poisoning by unspecified narcotics, assault (T40.603), poisoning by unspecified narcotics, undetermined (T40.604) and adverse effect of unspecified narcotics (T40.605).

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 has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.