2026 ICD-10-CM Diagnosis Code T50.0X5AAdverse effect of mineralocorticoids and their antagonists, initial encounter
T50.0X5A is a billable ICD-10-CM diagnosis code for adverse effect of mineralocorticoids and their antagonists, 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. Coders also document this condition as aldosterone antagonists adverse reaction. 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 T50.0X5A.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Aldosterone antagonists adverse reaction
- Fludrocortisone adverse reaction
- Mineralocorticoid adverse reaction
- Potassium canrenoate adverse reaction
- Potassium sparing diuretic adverse reaction
- Spironolactone 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 diuretics and other and unspecified drugs, medicaments and biological substances (T50). 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
Aldosterone
a hormone secreted by the adrenal cortex that regulates electrolyte and water balance by increasing the renal retention of sodium and the excretion of potassium.Cytochrome P-450 CYP11B2
a mitochondrial cytochrome p450 enzyme that catalyzes the 18-hydroxylation of steroids in the presence of molecular oxygen and nadph-specific flavoprotein. this enzyme, encoded by cyp11b2 gene, is important in the conversion of corticosterone to 18-hydroxycorticosterone and the subsequent conversion to aldosterone.Mineralocorticoid Receptor Antagonists
drugs that bind to and block the activation of mineralocorticoid receptors by mineralocorticoids such as aldosterone.Receptors, Mineralocorticoid
cytoplasmic proteins that specifically bind mineralocorticoids and mediate their cellular effects. the receptor with its bound ligand acts in the nucleus to induce transcription of specific segments of dna.Canrenoic Acid
a synthetic pregnadiene derivative with anti-aldosterone activity.Canrenone
a synthetic pregnadiene compound with anti-aldosterone activity.Fludrocortisone
a synthetic mineralocorticoid with anti-inflammatory activity.Spironolactone
a potassium sparing diuretic that acts by antagonism of aldosterone in the distal renal tubules. it is used mainly in the treatment of refractory edema in patients with congestive heart failure, nephrotic syndrome, or hepatic cirrhosis. its effects on the endocrine system are utilized in the treatments of hirsutism and acne but they can lead to adverse effects. (from martindale, the extra pharmacopoeia, 30th ed, p827)
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 T50.0X5A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T50.0X5AOverview
Is T50.0X5A (Adverse effect of mineralocorticoids and their antagonists) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of mineralocorticoids and their antagonists, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character A in T50.0X5A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of mineralocorticoids and their antagonists, such as an emergency visit or first evaluation.
What MS-DRG does T50.0X5A group to?
On inpatient claims, adverse effect of mineralocorticoids and their antagonists, 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 T50.0X5A be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of mineralocorticoids and their antagonists, 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 T50.0X5A?
Under the General Equivalence Mappings, adverse effect of mineralocorticoids and their antagonists, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E932.0 (adv eff corticosteroids). 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.
