T43.591 vs T43.594

T43.591 (Poisoning by other antipsychotics and neuroleptics, accidental (unintentional)) compared with T43.594 (Poisoning by other antipsychotics and neuroleptics, undetermined), from the official CMS tabular data. T43.591 and T43.594 code the same substance (Aminophenylpyridone) with a different intent.

Relationship

Informational

Drug table relationship

T43.591

Poisoning by other antipsychotics and neuroleptics, accidental (unintentional)

↔

T43.594

Poisoning by other antipsychotics and neuroleptics, undetermined

Same substance, different circumstance of exposure.

Same substance — undetermined intent (Aminophenylpyridone)

Accidental poisoning, intentional self-harm, assault, undetermined intent, adverse effect and underdosing are mutually exclusive columns — exactly one applies to a given encounter.

Source: CMS Table of Drugs and Chemicals

Can these codes be reported together?

Same substance, different intent. T43.591 and T43.594 code the same substance (Aminophenylpyridone) with a different circumstance of exposure.

From the CMS Table of Drugs and Chemicals: accidental poisoning, intentional self-harm, assault, undetermined intent, adverse effect and underdosing are mutually exclusive columns — only one of them applies to a given encounter.

Side by side

	T43.591Poisoning by other antipsychotics and neuroleptics, accidental (unintentional)	T43.594Poisoning by other antipsychotics and neuroleptics, undetermined
Billing status	Non-billable header Report instead: T43.591A, T43.591D, T43.591S	Non-billable header Report instead: T43.594A, T43.594D, T43.594S
Classification	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)	S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88)
Definition	Poisoning by other antipsychotics and neuroleptics, accidental (unintentional) is a non-billable ICD-10-CM category code (T43.591).	Poisoning by other antipsychotics and neuroleptics, undetermined is a non-billable ICD-10-CM category code (T43.594).
7th character	The appropriate 7th character is to be added to each code from category T43	The appropriate 7th character is to be added to each code from category T43
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	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
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)	code(s) to specify: manifestations of poisoning underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
Code first	, for adverse effects, the nature of the adverse effect, such as: adverse effect NOS (T88.7)	, for adverse effects, the nature of the adverse effect, such as: adverse effect NOS (T88.7)

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Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources