T42-T43 ICD-10-CM Code: Anticonvulsants & Psychotropics

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for T42-T43 in the official ICD-10-CM tabular list, quoted as published.

Don’t confuse T42-T43 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of T42-T43 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• O29.3— Excludes1 conflict (Conflict)

  Not coded here — these two are mutually exclusive.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of toxic reaction to local anesthesia in pregnancy moves the case to O29.3; the two are not reported together unless documented as unrelated.

  Full comparison: T42-T43 vs O29.3 →

• F10— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of abuse and dependence of psychoactive substances adds F10; it is not part of this code and both may be reported when both are documented.

  Full comparison: T42-T43 vs F10 →

• F19— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of abuse and dependence of psychoactive substances adds F19; it is not part of this code and both may be reported when both are documented.

  Full comparison: T42-T43 vs F19 →

• F55— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of abuse of non-dependence-producing substances adds F55; it is not part of this code and both may be reported when both are documented.

  Full comparison: T42-T43 vs F55 →

• D84.821— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of immunodeficiency due to drugs adds D84.821; it is not part of this code and both may be reported when both are documented.

  Full comparison: T42-T43 vs D84.821 →

• P00— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of drug reaction and poisoning affecting newborn adds P00; it is not part of this code and both may be reported when both are documented.

  Full comparison: T42-T43 vs P00 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Decision Points

The directives on this code's own record, as a pre-claim checklist.

1. Sequencing: 7 Code First instructions — the underlying condition is sequenced before this code when present. See the Code First notes
2. 4 Use Additional Code instructions — report the named additional code(s) when the documentation supports them. See the Use Additional Code notes
3. 1 Excludes1 entry — codes named there are generally not reported together with this code (Guidelines I.A.12.a). See the Excludes1 notes
4. 5 Excludes2 entries — those conditions are not part of this code and may be reported additionally when documented. See the Excludes2 notes

Checklist rows are derived from this code's own official directives; the wording of each check is MedCoder editorial. The official notes themselves are in the sections each row links to.

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T42-T43 in its code family, with their registry titles.

• T42 — Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs
• T43 — Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified