ICD-10-CM 2027 diagnosis code
T42.3X6Underdosing of barbiturates
T42.3X6 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.
Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS, effective October 1, 2026. Updated September 29, 2026. About our data
About T42.3X6
T42.3X6 is the ICD-10-CM diagnosis code for underdosing of barbiturates. It belongs to category T42 (poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs), 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 T42.3X (poisoning by, adverse effect of and underdosing of barbiturates), T42.3X6 is specifically for underdosing of barbiturates. Related codes cover poisoning by barbiturates, accidental (unintentional) (T42.3X1), poisoning by barbiturates, intentional self-harm (T42.3X2), poisoning by barbiturates, assault (T42.3X3), poisoning by barbiturates, undetermined (T42.3X4) and adverse effect of barbiturates (T42.3X5).
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 T42
Notes that apply from higher levels
Instructions written at a parent level also apply to T42.3X6.
› From T42.3 Poisoning by, adverse effect of and underdosing of barbiturates
- poisoning by, adverse effect of and underdosing of thiobarbiturates (T41.1-)
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
- Agrypnal — Underdosing
- Allobarbital — Underdosing
- Allylisopropylmalonylurea — Underdosing
- Allypropymal — Underdosing
- Alurate — Underdosing
- Amobarbital (sodium) — Underdosing
- Amylobarbitone — Underdosing
- Amytal (sodium) — Underdosing
- Anticonvulsant › barbiturate — Underdosing
- Anticonvulsant › combination (with barbiturate) — Underdosing
- Aprobarbital — Underdosing
- Barbenyl — Underdosing
- Barbital — Underdosing
- Barbital › sodium — Underdosing
- Barbitone — Underdosing
- Barbiturate NEC — Underdosing
- Barbiturate NEC › with tranquilizer — Underdosing
- Brallobarbital — Underdosing
- Butabarbital (sodium) — Underdosing
- Butabarbitone — Underdosing
- Butabarpal — Underdosing
- Butalbital — Underdosing
- Butallylonal — Underdosing
- Butethal — Underdosing
- Butisol (sodium) — Underdosing
- Butobarbital — Underdosing
- Butobarbital › sodium — Underdosing
- Butobarbitone — Underdosing
- Carbrital — Underdosing
- Central nervous system › depressants › barbiturates — 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 T42.3X6
Is T42.3X6 billable?
- No. T42.3X6 is a header code. Report one of its more specific subcodes instead.