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ICD-10-CM · FY 2026 APRIL UPDATE

T42

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

Diagnosis reference

Nonbillable category

This entry is a category or subcategory. Choose the appropriate billable descendant based on the clinical documentation.

Effective periodOctober 1, 2026–September 30, 2027
SourceCMS ICD-10-CM order file
ClassificationDiagnosis · clinical modification

Related entries

Up to 30 descendants in this category

CODEDESCRIPTIONTYPE
T42.0Poisoning by, adverse effect of and underdosing of hydantoin derivativesCategory
T42.0XPoisoning by, adverse effect of and underdosing of hydantoin derivativesCategory
T42.0X1Poisoning by hydantoin derivatives, accidental (unintentional)Category
T42.0X1APoisoning by hydantoin derivatives, accidental (unintentional), initial encounterBillable
T42.0X1DPoisoning by hydantoin derivatives, accidental (unintentional), subsequent encounterBillable
T42.0X1SPoisoning by hydantoin derivatives, accidental (unintentional), sequelaBillable
T42.0X2Poisoning by hydantoin derivatives, intentional self-harmCategory
T42.0X2APoisoning by hydantoin derivatives, intentional self-harm, initial encounterBillable
T42.0X2DPoisoning by hydantoin derivatives, intentional self-harm, subsequent encounterBillable
T42.0X2SPoisoning by hydantoin derivatives, intentional self-harm, sequelaBillable
T42.0X3Poisoning by hydantoin derivatives, assaultCategory
T42.0X3APoisoning by hydantoin derivatives, assault, initial encounterBillable
T42.0X3DPoisoning by hydantoin derivatives, assault, subsequent encounterBillable
T42.0X3SPoisoning by hydantoin derivatives, assault, sequelaBillable
T42.0X4Poisoning by hydantoin derivatives, undeterminedCategory
T42.0X4APoisoning by hydantoin derivatives, undetermined, initial encounterBillable
T42.0X4DPoisoning by hydantoin derivatives, undetermined, subsequent encounterBillable
T42.0X4SPoisoning by hydantoin derivatives, undetermined, sequelaBillable
T42.0X5Adverse effect of hydantoin derivativesCategory
T42.0X5AAdverse effect of hydantoin derivatives, initial encounterBillable
T42.0X5DAdverse effect of hydantoin derivatives, subsequent encounterBillable
T42.0X5SAdverse effect of hydantoin derivatives, sequelaBillable
T42.0X6Underdosing of hydantoin derivativesCategory
T42.0X6AUnderdosing of hydantoin derivatives, initial encounterBillable
T42.0X6DUnderdosing of hydantoin derivatives, subsequent encounterBillable
T42.0X6SUnderdosing of hydantoin derivatives, sequelaBillable
T42.1Poisoning by, adverse effect of and underdosing of iminostilbenesCategory
T42.1XPoisoning by, adverse effect of and underdosing of iminostilbenesCategory
T42.1X1Poisoning by iminostilbenes, accidental (unintentional)Category
T42.1X1APoisoning by iminostilbenes, accidental (unintentional), initial encounterBillable

Use the complete reference

This reference does not reproduce the full tabular hierarchy, inclusion notes, Excludes1/2 notes, sequencing instructions, or seventh-character rules. Review the official tables and coding guidelines.

Open official CMS files

ICD-10-CM codes describe diagnoses. They do not have an independent Medicare PFS reimbursement amount, and billability alone does not establish coverage.