T45.1X5A ICD-10-CM Code: Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter
Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.
Inpatient Payment Groups (MS-DRG)
MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0 (FY2026), Appendix B.
- MS-DRG 791 — PREMATURITY WITH MAJOR PROBLEMS (MDC 15)
- MS-DRG 793 — FULL TERM NEONATE WITH MAJOR PROBLEMS (MDC 15)
- MS-DRG 917 — POISONING AND TOXIC EFFECTS OF DRUGS WITH MCC (MDC 21)
- MS-DRG 918 — POISONING AND TOXIC EFFECTS OF DRUGS WITHOUT MCC (MDC 21)
A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.
Code Set: Valid FY2026 and FY2027. FY2026 took effect October 1, 2025.
Official Registry Overview & Definition
Adverse effect of antineoplastic and immunosuppressive drugs, initial encounter is a billable ICD-10-CM diagnosis code (T45.1X5A).
Official Tabular Instructional Notes
Sequencing, inclusion, and exclusion notes published for T45.1X5A 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.
- 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
Supplementary codes the tabular list directs you to add.
- Use additional 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
Does T45.1X5A require a 7th character?
Yes. The appropriate 7th character is to be added to each code from category T45.
Nearest Codes in This Family
Official ICD-10-CM classifications closest to T45.1X5A in its code family, with their registry titles.
- 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
- T45.1X5D — 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
Associated Substances (164)
Substances from the official ICD-10-CM Table of Drugs and Chemicals that map to this code.
- 2-Deoxy-5-fluorouridine
- 5-Deoxy-5-fluorouridine
- Aclarubicin
- Actinomycin C
- Actinomycin D
- Adriamycin
- Alkylating drug NEC
- Altretamine
- Amethopterin
- Aminoglutethimide
- Aminopterin sodium
- Amsacrine
- Anthramycin
- Anticancer agents NEC
- Antimetabolite
- Antimitotic agent
- Antineoplastic NEC
- Ara-C
- Asparaginase
- Azacitidine
- Azaribine
- Azaserine
- Azatepa
- Azathioprine
- BCNU
- Benzcarbimine
- Bleomycin
- Broxuridine
- Busulfan, busulphan
- Cactinomycin
- Cancer chemotherapy drug regimen
- Carboplatin
- Carboquone
- Carmofur
- Carmustine
- Chlorambucil
- Chlorhexamide
- Chlormethine
- Chloropurine
- Chromomycin A3
- Ciclosporin
- Cisplatin
- Colaspase
- Corynebacterium parvum
- Cycloleucin
- Cyclophosphamide
- Cyclosporin
- Cytarabine
- Cytosine arabinoside
- Cytoxan
- Dacarbazine
- Dactinomycin
- Daunomycin
- Daunorubicin
- Demecolcine
- Dibromodulcitol
- Dibromomannitol
- Doxifluridine
- Doxorubicin
- DTIC
- Elliptinium acetate
- Enocitabine
- Epirubicin
- Estramustine
- Etoglucid
- Etoposide
- FAC (fluorouracil + doxorubicin + cyclophosphamide)
- Floxuridine
- Fluorodeoxyuridine
- Fluorouracil
- Ftorafur
- Goserelin
- Hexamethylmelamine
- Hydroxycarbamide
- Hydroxyurea
- Idarubicin
- Ifosfamide
- Imidazole-4-carboxamide
- Immunosuppressive drug
- Inproquone
- Iproplatin
- Isophosphamide
- Leukeran
- Lomustine
- Lonidamine
- M-AMSA
- M-vac
- Mannomustine
- Matulane
- Mechlorethamine
- Melphalan
- Mercaptopurine
- Methotrexate
- Metoprine
- Mithramycin
- Mitobronitol
- Mitoguazone
- Mitolactol
- Mitomycin
- Mitopodozide
- Mitotane
- Mitoxantrone
- Mopidamol
- MOPP (mechlorethamine + vincristine + prednisone + procarbazine)
- Muromonab-CD3
- Mustine
- Myelobromal
- Myleran
- Nimustine
- Olivomycin
- Oncovin
- Paroxypropione
- Pentostatin
- Peplomycin
- Phenylalanine mustard
- Pipobroman
- Pirarubicin
- Plicamycin
- Porfiromycin
- Prednimustine
- Procarbazine
- Pteroyltriglutamate
- Purine analogue (antineoplastic)
- Purinethol
- Pyrimidine antagonist
- Razoxane
- Rubidomycin
- Rufocromomycin
- Sarcolysin
- Sarkomycin
- Semustine
- Streptozocin
- Streptozotocin
- Tauromustine
- Tegafur
- TEM
- Teniposide
- TEPA
- Thalidomide
- Thioguanine
- Thiotepa
- Tioguanine
- Treosulfan
- Tretamine
- Triaziquone
- Trichlormethine
- Trichlorotriethylamine
- Triethanomelamine
- Triethylenemelamine
- Triethylenephosphoramide
- Triethylenethiophosphoramide
- Trimetrexate
- Trimustine
- Trofosfamide
- Uracil mustard
- Uramustine
- Urethane
- Vinblastine
- Vincamine
- Vincristine
- Vindesine
- Vinorelbine tartrate
- Zinostatin
- Zorubicin