2026 ICD-10-CM Diagnosis Code T44.4X5AAdverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter
T44.4X5A is a billable ICD-10-CM diagnosis code for adverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 917 through 918. The code is not accepted as a principal diagnosis by the Medicare Code Editor. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T44.4X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Adverse reaction caused by decongestant
- Alpha-adrenoceptor agonist adverse reaction
- Amphetamine group adverse reaction
- Apraclonidine adverse reaction
- Central alpha-2 adrenergic receptor agonist adverse reaction
- Metaraminol adverse reaction
- Methoxamine adverse reaction
- Norepinephrine adverse reaction
- Oxedrine tartrate adverse reaction
- Phenylephrine adverse reaction
- Vasopressor adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of drugs primarily affecting the autonomic nervous system (T44). 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
Etilefrine
a phenylephrine-related beta-1 adrenergic and alpha adrenergic agonist used as a cardiotonic and antihypotensive agent.Metaraminol
a sympathomimetic agent that acts predominantly at alpha-1 adrenergic receptors. it has been used primarily as a vasoconstrictor in the treatment of hypotension.Methoxamine
an alpha-1 adrenergic agonist that causes prolonged peripheral vasoconstriction.Norepinephrine
precursor of epinephrine that is secreted by the adrenal medulla and is a widespread central and autonomic neurotransmitter. norepinephrine is the principal transmitter of most postganglionic sympathetic fibers, and of the diffuse projection system in the brain that arises from the locus ceruleus. it is also found in plants and is used pharmacologically as a sympathomimetic.Norepinephrine Plasma Membrane Transport Proteins
sodium chloride-dependent neurotransmitter symporters located primarily on the plasma membrane of noradrenergic neurons. they remove norepinephrine from the extracellular space by high affinity reuptake into presynaptic terminals. the norepinephrine transporter regulates signal amplitude and duration at noradrenergic synapses and is the target of adrenergic uptake inhibitors.Phenylethanolamine N-Methyltransferase
a methyltransferase that catalyzes the reaction of s-adenosyl-l-methionine and phenylethanolamine to yield s-adenosyl-l-homocysteine and n-methylphenylethanolamine. it can act on various phenylethanolamines and converts norepinephrine into epinephrine. (from enzyme nomenclature, 1992) ec 2.1.1.28.Receptors, Adrenergic
cell-surface proteins that bind epinephrine and/or norepinephrine with high affinity and trigger intracellular changes. the two major classes of adrenergic receptors, alpha and beta, were originally discriminated based on their cellular actions but now are distinguished by their relative affinity for characteristic synthetic ligands. adrenergic receptors may also be classified according to the subtypes of g-proteins with which they bind; this scheme does not respect the alpha-beta distinction.Phenylephrine
an alpha-1 adrenergic agonist used as a mydriatic, nasal decongestant, and cardiotonic 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
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T44.4X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T44.4X5AOverview
Is T44.4X5A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T44.4X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of predominantly alpha-adrenoreceptor agonists, such as an emergency visit or first evaluation.
What MS-DRG does T44.4X5A group to?
On inpatient claims, adverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter maps to MS-DRG 917, 918, with relative weights from 0.8571 to 1.5684 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T44.4X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
What is the ICD-9 equivalent of T44.4X5A?
Under the General Equivalence Mappings, adverse effect of predominantly alpha-adrenoreceptor agonists, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E941.2 (adv eff sympathomimetics). 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.
