2026 ICD-10-CM Diagnosis Code T48.4X5AAdverse effect of expectorants, initial encounter
T48.4X5A is a billable ICD-10-CM diagnosis code for adverse effect of expectorants, 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 T48.4X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acetylcysteine adverse reaction
- Adverse reaction to bromhexine
- Adverse reaction to expectorant
- Beractant adverse reaction
- Carbocisteine adverse reaction
- Dornase alfa adverse reaction
- Ipecacuanha adverse reaction
- Liquorice adverse reaction
- Mesna adverse reaction
- Methylcysteine adverse reaction
- Respiratory surfactant adverse reaction
- Terpenes adverse reaction
- Tyloxapol 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 agents primarily acting on smooth and skeletal muscles and the respiratory system (T48). 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
Acetylcysteine
the n-acetyl derivative of cysteine. it is used as a mucolytic agent to reduce the viscosity of mucous secretions. it has also been shown to have antiviral effects in patients with hiv due to inhibition of viral stimulation by reactive oxygen intermediates.Ambroxol
a metabolite of bromhexine that stimulates mucociliary action and clears the air passages in the respiratory tract. it is usually administered as the hydrochloride.Bromhexine
a mucolytic agent used in the treatment of respiratory disorders associated with viscid or excessive mucus. (from martindale, the extra pharmacopoeia, 30th ed, p744)Glycyrrhizic Acid
a widely used anti-inflammatory agent isolated from the licorice root. it is metabolized to glycyrrhetinic acid, which inhibits 11-beta-hydroxysteroid dehydrogenases and other enzymes involved in the metabolism of corticosteroids. therefore, glycyrrhizic acid, which is the main and sweet component of licorice, has been investigated for its ability to cause hypermineralocorticoidism with sodium retention and potassium loss, edema, increased blood pressure, as well as depression of the renin-angiotensin-aldosterone system.Guaifenesin
an expectorant that also has some muscle relaxing action. it is used in many cough preparations.
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 T48.4X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T48.4X5AOverview
Is T48.4X5A (Adverse effect of expectorants) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of expectorants, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T48.4X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of expectorants, such as an emergency visit or first evaluation.
What MS-DRG does T48.4X5A group to?
On inpatient claims, adverse effect of expectorants, 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 T48.4X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of expectorants, 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 T48.4X5A?
Under the General Equivalence Mappings, adverse effect of expectorants, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E945.5 (adv eff expectorants). 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.
