T42.3 is the authoritative medical code for Poisoning by, adverse effect of and underdosing of barbiturates. This classification is used in medical billing and clinical recording to specify the clinical criteria for poisoning by, adverse effect of and underdosing of barbiturates (ICD-10-CM T42.3), ensuring healthcare documentation aligns with 2026 federal coding standards.
Billing Status: NO. This is a clinician non-billable / parent hierarchy grouping in the ICD-10-CM system.
Official Registry Overview & Definition
Poisoning by, adverse effect of and underdosing of barbiturates is a non-billable ICD-10-CM category code T42.3. A more specific billable subcode must be selected for claims submission. 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): poisoning by, adverse effect of and underdosing of thiobarbiturates T41.1-; toxic reaction to local anesthesia in pregnancy O29.3-. Excludes2 (not included here): drug dependence and related mental and behavioral disorders due to psychoactive substance use F10.--F19.-; 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-). 7th character: The appropriate 7th character is to be added to each code from category T42.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T42.3 in the official ICD-10-CM tabular list.
Includes
Conditions the official ICD-10-CM tabular list includes under this code.
- 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
Conditions that can never be reported with this code; the two are mutually exclusive.
- poisoning by, adverse effect of and underdosing of thiobarbiturates T41.1-
- toxic reaction to local anesthesia in pregnancy O29.3-
Excludes2 — Not Included Here
Conditions not covered by this code, but which may be reported alongside it when both are present.
- drug dependence and related mental and behavioral disorders due to psychoactive substance use F10.--F19.-
- 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
Underlying conditions that must be sequenced before this code.
- , 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
Supplementary codes the tabular list directs you to add.
- 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-)
Frequently Asked Questions (FAQ) & Clinical Guidance
Can T42.3 be billed directly?
No. T42.3 (Poisoning by, adverse effect of and underdosing of barbiturates) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does T42.3 require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T42.
What can't be coded together with T42.3?
Per official ICD-10-CM Excludes1 instructions, T42.3 must not be reported together with: poisoning by, adverse effect of and underdosing of thiobarbiturates (T41.1-); toxic reaction to local anesthesia in pregnancy (O29.3-).
Can T42.3 be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, T42.3 and the following are not considered part of each other and may both be reported when both conditions are present: drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.--F19.-); abuse and dependence of psychoactive substances (F10-F19); abuse of non-dependence-producing substances (F55.-); immunodeficiency due to drugs (D84.821).
Does T42.3 need to be sequenced after another code?
Yes. 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).
Nearest Codes in This Family
Official ICD-10-CM classifications closest to T42.3 in its code family, with their registry titles.
- T42.3X — Poisoning by, adverse effect of and underdosing of barbiturates
- T42.3X1 — Poisoning by barbiturates, accidental (unintentional)
- T42.3X1A — Poisoning by barbiturates, accidental (unintentional), initial encounter
- T42.3X1D — Poisoning by barbiturates, accidental (unintentional), subsequent encounter
- T42.3X1S — Poisoning by barbiturates, accidental (unintentional), sequela
- T42.3X2 — Poisoning by barbiturates, intentional self-harm
- T42.3X2A — Poisoning by barbiturates, intentional self-harm, initial encounter
- T42.3X2D — Poisoning by barbiturates, intentional self-harm, subsequent encounter
- T42.3X2S — Poisoning by barbiturates, intentional self-harm, sequela
- T42.3X3 — Poisoning by barbiturates, assault
View all 25 codes in the T42.3X family