2026 ICD-10-CM Diagnosis Code T46.3X1SPoisoning by coronary vasodilators, accidental (unintentional), sequela
T46.3X1S is a billable ICD-10-CM diagnosis code for poisoning by coronary vasodilators, 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
T46.3X1S 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 dipyridamole overdose
- Accidental dipyridamole poisoning
- Accidental nitrate poisoning
- Accidental nitrite poisoning
- Dipyridamole overdose
- Glyceryl trinitrate overdose
- Isosorbide dinitrate overdose
- Isosorbide mononitrate overdose
- Methemoglobinemia due to nitrate poisoning
- Nitrate vasodilator overdose
- Poisoning by dipyridamole
- Poisoning by nitrate
- Poisoning by nitrite
- Poisoning by nitroglycerin
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 agents primarily affecting the cardiovascular system (T46). 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
Chromonar
a coronary vasodilator agent.Dilazep
coronary vasodilator with some antiarrhythmic activity.Aspirin, Dipyridamole Drug Combination
a drug combination of aspirin and dipyridamole that functions as a platelet aggregation inhibitor, used to prevent thrombosis and stroke in transient ischemic attack patients.Dipyridamole
a phosphodiesterase inhibitor that blocks uptake and metabolism of adenosine by erythrocytes and vascular endothelial cells. dipyridamole also potentiates the antiaggregating action of prostacyclin. (from ama drug evaluations annual, 1994, p752)Erythrityl Tetranitrate
a vasodilator with general properties similar to nitroglycerin. (from martindale, the extra pharmacopoeia, 30th ed, p1020)Heptaminol
an amino alcohol that has been used as a myocardial stimulant and vasodilator and to relieve bronchospasm. its most common therapeutic use is in orthostatic hypotension. the mechanism of heptaminol's therapeutic actions is not well understood although it has been suggested to affect catecholamine release or calcium metabolism.Hexobendine
a potent vasoactive agent that dilates cerebral and coronary arteries, but slightly constricts femoral arteries, without any effects on heart rate, blood pressure or cardiac output.Isosorbide Dinitrate
a vasodilator used in the treatment of angina pectoris. its actions are similar to nitroglycerin but with a slower onset of action.Khellin
a vasodilator that also has bronchodilatory action. it has been employed in the treatment of angina pectoris, in the treatment of asthma, and in conjunction with ultraviolet light a, has been tried in the treatment of vitiligo. (from martindale, the extra pharmacopoeia, 30th ed, p1024)Molsidomine
a morpholinyl sydnone imine ethyl ester, having a nitrogen in place of the keto oxygen. it acts as nitric oxide donors and is a vasodilator that has been used in angina pectoris.Nicorandil
a derivative of the niacinamide that is structurally combined with an organic nitrate. it is a potassium-channel opener that causes vasodilatation of arterioles and large coronary arteries. its nitrate-like properties produce venous vasodilation through stimulation of guanylate cyclase.Oxyfedrine
a drug used in the treatment of angina pectoris, heart failure, conduction defects, and myocardial infarction. it is a partial agonist at beta adrenergic receptors and acts as a coronary vasodilator and cardiotonic agent.Prenylamine
a drug formerly used in the treatment of angina pectoris but superseded by less hazardous drugs. prenylamine depletes myocardial catecholamine stores and has some calcium channel blocking activity. (from martindale, the extra pharmacopoeia, 30th ed, p1406)Trapidil
a coronary vasodilator agent.
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 T46.3X1S to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T46.3X1SOverview
Is T46.3X1S a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report poisoning by coronary vasodilators, accidental (unintentional), sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T46.3X1S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the poisoning by coronary vasodilators, accidental (unintentional) itself has resolved, not the original event.
What MS-DRG does T46.3X1S group to?
When poisoning by coronary vasodilators, 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 T46.3X1S 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 coronary vasodilators, accidental (unintentional), sequela on inpatient claims.
What is the ICD-9 equivalent of T46.3X1S?
Under the General Equivalence Mappings, poisoning by coronary vasodilators, 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.
