T42Header code — not billable

Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs

Short description: Antiepileptic, sedative- hypnotic and antiparkinsonism drugs

Chapter
19. Injury, poisoning and certain other consequences of external causes
Category
T42
Effective date
October 1, 2026

Related codes in category T42

T42.0Hydantoin derivativesT42.0XHydantoin derivativesT42.0X1Poisoning by hydantoin derivatives, accidentalT42.0X1APoisoning by hydantoin derivatives, accidental, initYesT42.0X1DPoisoning by hydantoin derivatives, accidental, subsYesT42.0X1SPoisoning by hydantoin derivatives, accidental, sequelaYesT42.0X2Poisoning by hydantoin derivatives, intentional self-harmT42.0X2APoisoning by hydantoin derivatives, self-harm, initYesT42.0X2DPoisoning by hydantoin derivatives, self-harm, subsYesT42.0X2SPoisoning by hydantoin derivatives, self-harm, sequelaYesT42.0X3Poisoning by hydantoin derivatives, assaultT42.0X3APoisoning by hydantoin derivatives, assault, init encntrYes

Frequently asked questions

What is ICD-10 code T42?

T42 is an ICD-10-CM diagnosis code for Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs.

Is T42 a billable code?

No. T42 is a category/header code, not billable on its own — use one of its more specific child codes instead.

What ICD-10-CM chapter is T42 in?

T42 falls under Chapter 19: Injury, poisoning and certain other consequences of external causes.

When did T42 become effective?

T42 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.

What other codes are related to T42?

T42 belongs to category T42, which includes 12 other codes — see the related codes list on this page.

ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.