2026 ICD-10-CM Diagnosis Code T43.3X1SPoisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela
T43.3X1S is a billable ICD-10-CM diagnosis code for poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Present on Admission (POA)Billing
T43.3X1S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Accidental chlorpromazine overdose
- Accidental fluphenazine decanoate overdose
- Accidental fluphenazine enanthate overdose
- Accidental levomeprazine poisoning
- Accidental levomepromazine overdose
- Accidental pericyazine overdose
- Accidental pericyazine poisoning
- Accidental perphenazine overdose
- Accidental perphenazine poisoning
- Accidental pipothiazine overdose
- Accidental pipothiazine poisoning
- Accidental poisoning by chlorpromazine
- Accidental poisoning by fluphenazine
- Accidental poisoning by phenothiazine-based tranquilizer
- Accidental poisoning by prochlorperazine
- Accidental poisoning by promazine
- Accidental prochlorperazine overdose
- Accidental promazine overdose
- Accidental thiethylperazine overdose
- Accidental thiethylperazine poisoning
- Accidental thioridazine overdose
- Accidental thioridazine poisoning
- Accidental trifluoperazine overdose
- Accidental trifluoperazine poisoning
- Chlorpromazine overdose
- Fluphenazine decanoate overdose
- Fluphenazine enanthate overdose
- Levomeprazine overdose
- Levomepromazine poisoning
- Pericyazine overdose
- Pericyazine poisoning
- Perphenazine overdose
- Perphenazine poisoning
- Phenothiazine and/or phenothiazine derivative overdose
- Phenothiazine poisoning
- Pipothiazine overdose
- Pipothiazine poisoning
- Poisoning by chlorpromazine
- Poisoning by fluphenazine
- Poisoning by phenothiazine-based tranquilizer
- Poisoning by prochlorperazine
- Poisoning by promazine
- Prochlorperazine overdose
- Promazine overdose
- Thiethylperazine overdose
- Thiethylperazine poisoning
- Thioridazine overdose
- Thioridazine poisoning
- Trifluoperazine overdose
- Trifluoperazine poisoning
Coding GuidelinesGuidance
When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined). If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of psychotropic drugs, not elsewhere classified (T43). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Acepromazine
a phenothiazine that is used in the treatment of psychoses.Chlorpromazine
the prototypical phenothiazine antipsychotic drug. like the other drugs in this class chlorpromazine's antipsychotic actions are thought to be due to long-term adaptation by the brain to blocking dopamine receptors. chlorpromazine has several other actions and therapeutic uses, including as an antiemetic and in the treatment of intractable hiccup.Fluphenazine
a phenothiazine used in the treatment of psychoses. its properties and uses are generally similar to those of chlorpromazine.Mesoridazine
a phenothiazine antipsychotic with effects similar to chlorpromazine.Methotrimeprazine
a phenothiazine with pharmacological activity similar to that of both chlorpromazine and promethazine. it has the histamine-antagonist properties of the antihistamines together with central nervous system effects resembling those of chlorpromazine. (from martindale, the extra pharmacopoeia, 30th ed, p604)Perazine
a phenothiazine antipsychotic with actions and uses similar to those of chlorpromazine. extrapyramidal symptoms may be more common than other side effects.Perphenazine
an antipsychotic phenothiazine derivative with actions and uses similar to those of chlorpromazine.Prochlorperazine
a phenothiazine antipsychotic used principally in the treatment of nausea; vomiting; and vertigo. it is more likely than chlorpromazine to cause extrapyramidal disorders. (from martindale, the extra pharmacopoeia, 30th ed, p612)Promazine
a phenothiazine with actions similar to chlorpromazine but with less antipsychotic activity. it is primarily used in short-term treatment of disturbed behavior and as an antiemetic.Thiethylperazine
a dopamine antagonist that is particularly useful in treating the nausea and vomiting associated with anesthesia, mildly emetic cancer chemotherapy agents, radiation therapy, and toxins. this piperazine phenothiazine does not prevent vertigo or motion sickness. (from ama drug evaluations annual, 1994, p457)Thioridazine
a phenothiazine antipsychotic used in the management of phycoses, including schizophrenia.Trifluoperazine
a phenothiazine with actions similar to chlorpromazine. it is used as an antipsychotic and an antiemetic.Triflupromazine
a phenothiazine used as an antipsychotic agent and as an antiemetic.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Medication Errors
Medicines treat infectious diseases, prevent problems from chronic diseases, and ease pain. But medicines can also cause harmful reactions if not used correctly. Errors can happen in the hospital, at the health care provider's office, at the pharmacy, or at home. You can help prevent errors by:
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T43.3X1S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T43.3X1SOverview
Is T43.3X1S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T43.3X1S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T43.3X1S group to?
When poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela is the principal diagnosis on an inpatient stay, it groups to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Is T43.3X1S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T43.3X1S?
Under the General Equivalence Mappings, poisoning by phenothiazine antipsychotics and neuroleptics, accidental (unintentional), sequela converts to ICD-9-CM 909.0 (late eff drug poisoning) and E929.2 (late eff acc poisoning). The mapping is approximate, so confirm the match fits the documentation.
Footnotes
[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.
