T43
Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified
T43 is a non-billable ICD-10-CM code category for poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified. Report a more specific code from it instead. It is part of the FY2027 code set, effective October 1, 2026. The more specific codes under it are T43.0 Poisoning by, adverse effect of and underdosing of tricyclic and tetracyclic antidepressants; T43.1 Poisoning by, adverse effect of and underdosing of monoamine-oxidase-inhibitor antidepressants; T43.2 Poisoning by, adverse effect of and underdosing of other and unspecified antidepressants; T43.3 Poisoning by, adverse effect of and underdosing of phenothiazine antipsychotics and neuroleptics and 5 more. Its coding notes include a Code first instruction, a Use additional code instruction, 1 Excludes1 entry and 13 Excludes2 entries.
7th characters
Every code below needs one of these.
The appropriate 7th character is to be added to each code from category T43
- Ainitial encounter
- Dsubsequent encounter
- Ssequela
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
T36-T65 codes already include the substance and the intent, so no additional external cause code is required. Do not code directly from the Table of Drugs and Chemicals.
Code first
If the underlying condition listed here is present and known, sequence it first.
Also from chapter/block level (7 notes)
Use additional code
Add the listed code as a secondary code, if known.
Also from chapter/block level (5 notes)
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (7 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Includes
Further defines or gives examples of the content of the category.
Also from chapter/block level (4 notes)
- 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
Notes
Also from chapter/block level (3 notes)
- The drug giving rise to the adverse effect should be identified by use of codes from categories T36-T50 with fifth or sixth character 5.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
More specific codes under T43 9
- T43.0Poisoning by, adverse effect of and underdosing of tricyclic and tetracyclic antidepressantsHeader
- T43.1Poisoning by, adverse effect of and underdosing of monoamine-oxidase-inhibitor antidepressantsHeader
- T43.2Poisoning by, adverse effect of and underdosing of other and unspecified antidepressantsHeader
- T43.3Poisoning by, adverse effect of and underdosing of phenothiazine antipsychotics and neurolepticsHeader
- T43.4Poisoning by, adverse effect of and underdosing of butyrophenone and thiothixene neurolepticsHeader
- T43.5Poisoning by, adverse effect of and underdosing of other and unspecified antipsychotics and neurolepticsHeader
- T43.6Poisoning by, adverse effect of and underdosing of psychostimulantsHeader
- T43.8Poisoning by, adverse effect of and underdosing of other psychotropic drugsHeader
- T43.9Poisoning by, adverse effect of and underdosing of unspecified psychotropic drugHeader