ICD-10-CM 2027 diagnosis code
T42Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs
T42 is a header code, so it can't be reported by itself. Choose one of the 9 more specific codes beneath it.Short description: Antiepileptic, sedative- hypnotic and antiparkinsonism drugs
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
T42 is the ICD-10-CM diagnosis code for poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs. It belongs to 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 9 subcodes must be used instead.
To report this condition, pick the subcode that matches the documentation: T42.0 (derivatives), T42.1 (iminostilbenes), T42.2 (oxazolidinediones), T42.3 (barbiturates), T42.4 (benzodiazepines), T42.5 (antiepileptics), T42.6 (drugs), T42.7 (drugs) and 1 more.
The conditions in its Excludes2 note aren't part of T42, but may be coded alongside it if the patient has both: drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.--F19.-).
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Specific codes under T42
- T42.0Poisoning by, adverse effect of and underdosing of hydantoin derivatives
- T42.0XPoisoning by, adverse effect of and underdosing of hydantoin derivatives
- T42.0X1Poisoning by hydantoin derivatives, accidental (unintentional)
- T42.0X2Poisoning by hydantoin derivatives, intentional self-harm
- T42.0X3Poisoning by hydantoin derivatives, assault
- T42.0X4Poisoning by hydantoin derivatives, undetermined
- T42.0X5Adverse effect of hydantoin derivatives
- T42.0X6Underdosing of hydantoin derivatives
- T42.0XPoisoning by, adverse effect of and underdosing of hydantoin derivatives
- T42.1Poisoning by, adverse effect of and underdosing of iminostilbenes
- T42.2Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
- T42.2XPoisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
- T42.2X1Poisoning by succinimides and oxazolidinediones, accidental (unintentional)
- T42.2X2Poisoning by succinimides and oxazolidinediones, intentional self-harm
- T42.2X3Poisoning by succinimides and oxazolidinediones, assault
- T42.2X4Poisoning by succinimides and oxazolidinediones, undetermined
- T42.2X5Adverse effect of succinimides and oxazolidinediones
- T42.2X6Underdosing of succinimides and oxazolidinediones
- T42.2XPoisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
- T42.3Poisoning by, adverse effect of and underdosing of barbiturates
- T42.4Poisoning by, adverse effect of and underdosing of benzodiazepines
- T42.5Poisoning by, adverse effect of and underdosing of mixed antiepileptics
- T42.5XPoisoning by, adverse effect of and underdosing of antiepileptics
- T42.5X1Poisoning by mixed antiepileptics, accidental (unintentional)
- T42.5X2Poisoning by mixed antiepileptics, intentional self-harm
- T42.5X3Poisoning by mixed antiepileptics, assault
- T42.5X4Poisoning by mixed antiepileptics, undetermined
- T42.5X5Adverse effect of mixed antiepileptics
- T42.5X6Underdosing of mixed antiepileptics
- T42.5XPoisoning by, adverse effect of and underdosing of antiepileptics
- T42.6Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
- T42.6XPoisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
- T42.6X1Poisoning by other antiepileptic and sedative-hypnotic drugs, accidental (unintentional)
- T42.6X2Poisoning by other antiepileptic and sedative-hypnotic drugs, intentional self-harm
- T42.6X3Poisoning by other antiepileptic and sedative-hypnotic drugs, assault
- T42.6X4Poisoning by other antiepileptic and sedative-hypnotic drugs, undetermined
- T42.6X5Adverse effect of other antiepileptic and sedative-hypnotic drugs
- T42.6X6Underdosing of other antiepileptic and sedative-hypnotic drugs
- T42.6XPoisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
- T42.7Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs
- T42.71Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, accidental (unintentional)
- T42.72Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, intentional self-harm
- T42.73Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, assault
- T42.74Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, undetermined
- T42.75Adverse effect of unspecified antiepileptic and sedative-hypnotic drugs
- T42.76Underdosing of unspecified antiepileptic and sedative-hypnotic drugs
- T42.8Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
- T42.8XPoisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
- T42.8X1Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, accidental (unintentional)
- T42.8X2Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, intentional self-harm
- T42.8X3Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, assault
- T42.8X4Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined
- T42.8X5Adverse effect of antiparkinsonism drugs and other central muscle-tone depressants
- T42.8X6Underdosing of antiparkinsonism drugs and other central muscle-tone depressants
- T42.8XPoisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
Coding notes
Notes that apply from higher levels
Instructions written at a parent level also apply to T42.
Codes whose notes reference T42
- F13.2Excludes2
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 T42
Is T42 billable?
- No. T42 is a header code. Report one of its more specific subcodes instead.