ICD-10-CM 2027 diagnosis code
T40.6Poisoning by, adverse effect of and underdosing of other and unspecified narcotics
T40.6 is a header code, so it can't be reported by itself. Choose one of the 2 more specific codes beneath it and add the required 7th character.Short description: And unsp narcotics
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About T40.6
T40.6 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of other and 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 2 subcodes must be used instead.
Within T40, choose T40.6 (by, adverse effect of and underdosing of other and unspecified narcotics) only when documentation doesn't support a more specific option: by, adverse effect of and underdosing of opium (T40.0), by and adverse effect of heroin (T40.1), by, adverse effect of and underdosing of other opioids (T40.2), by, adverse effect of and underdosing of methadone (T40.3), by, adverse effect of and underdosing of other synthetic narcotics (T40.4), by, adverse effect of and underdosing of cocaine (T40.5), by, adverse effect of and underdosing of cannabis (derivatives) (T40.7), by and adverse effect of lysergide [LSD] (T40.8) and 1 more.
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.
7th character
The appropriate 7th character is to be added to each code from category T40
- T40.60Poisoning by, adverse effect of and underdosing of unspecified narcotics
- T40.601Poisoning by unspecified narcotics, accidental (unintentional)
- T40.602Poisoning by unspecified narcotics, intentional self-harm
- T40.603Poisoning by unspecified narcotics, assault
- T40.604Poisoning by unspecified narcotics, undetermined
- T40.605Adverse effect of unspecified narcotics
- T40.606Underdosing of unspecified narcotics
- T40.69Poisoning by, adverse effect of and underdosing of other narcotics
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Notes that apply from higher levels
Instructions written at a parent level also apply to T40.6.
Broader instructions also apply from 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.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about T40.6
Is T40.6 billable?
- No. T40.6 is a header code. Report one of its more specific subcodes instead.