T40.604 is the authoritative medical code for Poisoning by unspecified narcotics, undetermined. This classification is used in medical billing and clinical recording to specify the clinical criteria for poisoning by unspecified narcotics, undetermined (ICD-10-CM T40.604), 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 unspecified narcotics, undetermined is a non-billable ICD-10-CM category code T40.604. 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 T40.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T40.604 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 T40.604 be billed directly?
No. T40.604 (Poisoning by unspecified narcotics, undetermined) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does T40.604 require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T40.
What can't be coded together with T40.604?
Per official ICD-10-CM Excludes1 instructions, T40.604 must not be reported together with: toxic reaction to local anesthesia in pregnancy (O29.3-).
Can T40.604 be reported alongside related conditions?
Per official ICD-10-CM Excludes2 instructions, T40.604 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 T40.604 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 T40.604 in its code family, with their registry titles.
- T40 — Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
- T40-T41 — Analgesics & Antipyretics (T40-T41)
- T40.0 — Poisoning by, adverse effect of and underdosing of opium
- T40.0X — Poisoning by, adverse effect of and underdosing of opium
- T40.0X1 — Poisoning by opium, accidental (unintentional)
- T40.0X1A — Poisoning by opium, accidental (unintentional), initial encounter
- T40.0X1D — Poisoning by opium, accidental (unintentional), subsequent encounter
- T40.0X1S — Poisoning by opium, accidental (unintentional), sequela
- T40.0X2 — Poisoning by opium, intentional self-harm
- T40.0X2A — Poisoning by opium, intentional self-harm, initial encounter
View all 40 codes in the T40 family
Associated Substances (2)
Substances from the official ICD-10-CM Table of Drugs and Chemicals that map to this code.
- Narcotic (drug)
- Opiate NEC