ICD-10-CM 2027 diagnosis code
T43.016Underdosing of tricyclic antidepressants
T43.016 is a header code, so it can't be reported by itself. Choose one of the 3 more specific codes beneath it and add the required 7th character.
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About T43.016
T43.016 is the ICD-10-CM diagnosis code for underdosing of tricyclic antidepressants. It belongs to category T43 (poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified), block T36-T50 (poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is a header code, so it can't be reported by itself; one of its 3 subcodes must be used instead.
Within T43.01 (poisoning by, adverse effect of and underdosing of tricyclic antidepressants), T43.016 is specifically for underdosing of tricyclic antidepressants. Related codes cover poisoning by tricyclic antidepressants, accidental (unintentional) (T43.011), poisoning by tricyclic antidepressants, intentional self-harm (T43.012), poisoning by tricyclic antidepressants, assault (T43.013), poisoning by tricyclic antidepressants, undetermined (T43.014) and adverse effect of tricyclic antidepressants (T43.015).
Codes in this range require a 7th character: A for initial encounter, D for subsequent encounter and S for sequela. Use placeholder "X" characters to fill any empty positions before the 7th character.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
7th character
The appropriate 7th character is to be added to each code from category T43
Notes that apply from higher levels
Instructions written at a parent level also apply to T43.016.
› From T43 Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified
Broader instructions also apply from T36-T50 Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances and Chapter 19: Injury, poisoning and certain other consequences of external causes.
Table of Drugs & Neoplasms entries
- Allegron — Underdosing
- Amineptine — Underdosing
- Amitriptyline — Underdosing
- Amitriptylinoxide — Underdosing
- Amoxapine — Underdosing
- Antidepressant › tricyclic — Underdosing
- Butriptyline — Underdosing
- Chlorimipramine — Underdosing
- Cianopramine — Underdosing
- Clomipramine — Underdosing
- Desipramine — Underdosing
- Desmethylimipramine — Underdosing
- Dibenzepin — Underdosing
- Dosulepin — Underdosing
- Dothiepin — Underdosing
- Doxepin — Underdosing
- Imipramine — Underdosing
- Iprindole — Underdosing
- Laroxyl — Underdosing
- Lofepramine — Underdosing
- Melitracen — Underdosing
- Metapramine — Underdosing
- Nortriptyline — Underdosing
- Noxiptiline — Underdosing
- Opipramol — Underdosing
- Pertofrane — Underdosing
- Protriptyline — Underdosing
- Quinupramine — Underdosing
- Saroten — Underdosing
- Sinequan — Underdosing
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about T43.016
Is T43.016 billable?
- No. T43.016 is a header code. Report one of its more specific subcodes instead.