All ICD10 Codes

T43

Non-Billable
ChapterS00–T88
Rankcategory
Official Description

Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified

Metadata & Insights
  • •2026 ICD-10-CM Edition - Effective October 1, 2025.
  • •Non-billable category (requires more specific sub-code).
  • •Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88).

CH19 Parent Instructions

Excludes2(Not included here)
Use Additional Code
  • code to identify any retained foreign body, if applicable (Z18.-)

T36-T50 Parent Instructions

Includes
  • adverse effect of correct substance properly administered
  • poisoning by overdose of substance
  • poisoning by wrong substance given or taken in error
  • underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed
Excludes1(Not coded here)
  • toxic reaction to local anesthesia in pregnancy (O29.3-)
Excludes2(Not included here)
  • abuse and dependence of psychoactive substances (F10-F19)
  • abuse of non-dependence-producing substances (F55.-)
  • immunodeficiency due to drugs (D84.821)
  • drug reaction and poisoning affecting newborn (P00-P96)
  • pathological drug intoxication (inebriation) (F10-F19)
Code First
  • , for adverse effects, the nature of the adverse effect, such as:
  • adverse effect NOS (T88.7)
  • aspirin gastritis (K29.-)
  • blood disorders (D56-D76)
  • contact dermatitis (L23-L25)
  • dermatitis due to substances taken internally (L27.-)
  • nephropathy (N14.0-N14.2)
Use Additional Code
  • code(s) to specify:
  • manifestations of poisoning
  • underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
  • underdosing of medication regimen (Z91.12-, Z91.13-)

Instructional Notes

Excludes2(Not included here)
  • appetite depressants (T50.5-)
  • barbiturates (T42.3-)
  • benzodiazepines (T42.4-)
  • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.- -F19.-)
  • methaqualone (T42.6-)
  • psychodysleptics [hallucinogens] (T40.7-T40.9-)

Clinical Hierarchy

CH19Injury, poisoning and certain other consequences of external causes (S00-T88)
T36-T50Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)
T43Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified
T43.0Poisoning by, adverse effect of and underdosing of tricyclic and tetracyclic antidepressants
T43.1Poisoning by, adverse effect of and underdosing of monoamine-oxidase-inhibitor antidepressants
T43.2Poisoning by, adverse effect of and underdosing of other and unspecified antidepressants
T43.3Poisoning by, adverse effect of and underdosing of phenothiazine antipsychotics and neuroleptics
T43.4Poisoning by, adverse effect of and underdosing of butyrophenone and thiothixene neuroleptics
T43.5Poisoning by, adverse effect of and underdosing of other and unspecified antipsychotics and neuroleptics
T43.6Poisoning by, adverse effect of and underdosing of psychostimulants
T43.8Poisoning by, adverse effect of and underdosing of other psychotropic drugs
T43.9Poisoning by, adverse effect of and underdosing of unspecified psychotropic drug

Applicable Ancestor Context

The following parent sections contain instructions or notes that apply to T43:

blockT36-T50
Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50)
View context instructions
chapterCH19
Injury, poisoning and certain other consequences of external causes (S00-T88)
View context instructions

Alphabetic Index Mentions

These are Diagnosis Index lookup paths that route to T43. Use them as entry terms for search, then confirm final coding instructions in the Tabular List and notes above.

1 raw paths
Syndrome1 unique routes
antidepressant discontinuation→T43

MS-DRG Classification

2026

No direct MS-DRG triggers identified.

Cross Reference

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