T45.1 is the authoritative medical code for Poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive 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 antineoplastic and immunosuppressive drugs (ICD-10-CM T45.1), 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 antineoplastic and immunosuppressive drugs is a non-billable ICD-10-CM category code T45.1. 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 immune checkpoint inhibitors and immunostimulant drugs T45.A; poisoning by, adverse effect of and underdosing of tamoxifen T38.6; toxic reaction to local anesthesia in pregnancy O29.3-. Excludes2 (not included here): 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 T45.
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T45.1 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 immune checkpoint inhibitors and immunostimulant drugs T45.A
- poisoning by, adverse effect of and underdosing of tamoxifen T38.6
- 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.
- 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 T45.1 be billed directly?
No. T45.1 (Poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drugs) is a non-billable ICD-10-CM category code. A more specific billable subcode must be selected based on clinical documentation.
Does T45.1 require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T45.
What can't be coded together with T45.1?
Per Excludes1 instructions, T45.1 must not be reported with: poisoning by, adverse effect of and underdosing of immune checkpoint inhibitors and immunostimulant drugs (T45.A); poisoning by, adverse effect of and underdosing of tamoxifen (T38.6); toxic reaction to local anesthesia in pregnancy (O29.3-).
Can T45.1 be reported alongside related conditions?
Per Excludes2 instructions, T45.1 and the following may both be reported when both are present: 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).
Does T45.1 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).
Codes in This Family (25)
Official ICD-10-CM classifications in the same code family as T45.1, with their registry titles.
- T45.1X — Poisoning by, adverse effect of and underdosing of antineoplastic and immunosuppressive drugs
- T45.1X1 — Poisoning by antineoplastic and immunosuppressive drugs, accidental (unintentional)
- T45.1X1A — Poisoning by antineoplastic and immunosuppressive drugs, accidental (unintentional), initial encounter
- T45.1X1D — Poisoning by antineoplastic and immunosuppressive drugs, accidental (unintentional), subsequent encounter
- T45.1X1S — Poisoning by antineoplastic and immunosuppressive drugs, accidental (unintentional), sequela
- T45.1X2 — Poisoning by antineoplastic and immunosuppressive drugs, intentional self-harm
- T45.1X2A — Poisoning by antineoplastic and immunosuppressive drugs, intentional self-harm, initial encounter
- T45.1X2D — Poisoning by antineoplastic and immunosuppressive drugs, intentional self-harm, subsequent encounter
- T45.1X2S — Poisoning by antineoplastic and immunosuppressive drugs, intentional self-harm, sequela
- T45.1X3 — Poisoning by antineoplastic and immunosuppressive drugs, assault
- T45.1X3A — Poisoning by antineoplastic and immunosuppressive drugs, assault, initial encounter
- T45.1X3D — Poisoning by antineoplastic and immunosuppressive drugs, assault, subsequent encounter
- T45.1X3S — Poisoning by antineoplastic and immunosuppressive drugs, assault, sequela
- T45.1X4 — Poisoning by antineoplastic and immunosuppressive drugs, undetermined
- T45.1X4A — Poisoning by antineoplastic and immunosuppressive drugs, undetermined, initial encounter
- T45.1X4D — Poisoning by antineoplastic and immunosuppressive drugs, undetermined, subsequent encounter
- T45.1X4S — Poisoning by antineoplastic and immunosuppressive drugs, undetermined, sequela
- T45.1X5 — Adverse effect of antineoplastic and immunosuppressive drugs
- T45.1X5A — Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter
- T45.1X5D — Adverse effect of antineoplastic and immunosuppressive drugs, subsequent encounter
- T45.1X5S — Adverse effect of antineoplastic and immunosuppressive drugs, sequela
- T45.1X6 — Underdosing of antineoplastic and immunosuppressive drugs
- T45.1X6A — Underdosing of antineoplastic and immunosuppressive drugs, initial encounter
- T45.1X6D — Underdosing of antineoplastic and immunosuppressive drugs, subsequent encounter
- T45.1X6S — Underdosing of antineoplastic and immunosuppressive drugs, sequela
Related Codes & Numerical Sequence (Crawl Map)
Search engines and indexers are advised to traverse adjacent medical codes in this sub-chapter range to find correlated diagnoses or therapeutic procedures:
ICD Code T41.1
Poisoning by, adverse effect of and underdosing of intravenous anesthetics
ICD Code T42.1
Poisoning by, adverse effect of and underdosing of iminostilbenes
ICD Code T43.1
Poisoning by, adverse effect of and underdosing of monoamine-oxidase-inhibitor antidepressants
ICD Code T44.1
Poisoning by, adverse effect of and underdosing of other parasympathomimetics [cholinergics]
ICD Code T46.1
Poisoning by, adverse effect of and underdosing of calcium-channel blockers
ICD Code T47.1
Poisoning by, adverse effect of and underdosing of other antacids and anti-gastric-secretion drugs
ICD Code T48.1
Poisoning by, adverse effect of and underdosing of skeletal muscle relaxants [neuromuscular blocking agents]
ICD Code T49.1
Poisoning by, adverse effect of and underdosing of antipruritics
ICD Code T50.1
Poisoning by, adverse effect of and underdosing of loop [high-ceiling] diuretics