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ICD-10-CM 2027 diagnosis code

T42.4XPoisoning by, adverse effect of and underdosing of benzodiazepines

Not billable — use a more specific codeRequires 7th character

T42.4X is a header code, so it can't be reported by itself. Choose one of the 6 more specific codes beneath it and add the required 7th character.Short description: Benzodiazepines

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 T42.4X

T42.4X is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of benzodiazepines. It belongs to category T42 (poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs), 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 6 subcodes must be used instead.

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 T42

  • Ainitial encounter
  • Dsubsequent encounter
  • Ssequela

Notes that apply from higher levels

Instructions written at a parent level also apply to T42.4X.

› From T42 Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs
Excludes2
  • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.--F19.-)

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

  1. 2016
  2. 2017
  3. 2018
  4. 2019
  5. 2020
  6. 2021
  7. 2022
  8. 2023
  9. 2024
  10. 2025
  11. 2026
  12. 2027
  • FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
  • No changes since FY2016.

Common questions about T42.4X

Is T42.4X billable?

No. T42.4X is a header code. Report one of its more specific subcodes instead.