T42.7 is the authoritative medical code for Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs. This classification is used in medical billing and clinical recording to specify the clinical criteria for poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs (ICD-10-CM T42.7), 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 unspecified antiepileptic and sedative-hypnotic drugs is a non-billable ICD-10-CM category code T42.7. 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): 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 T42.7 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.
- 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 T42.7 be billed directly?
No. T42.7 (Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does T42.7 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 T42.7?
Per official ICD-10-CM Excludes1 instructions, T42.7 must not be reported together with: toxic reaction to local anesthesia in pregnancy (O29.3-).
Can T42.7 be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, T42.7 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 T42.7 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).