2026 ICD-10-CM Diagnosis Code T50.7X6AUnderdosing of analeptics and opioid receptor antagonists, initial encounter

ICD-10-CM CodesS00–T88T36-T50T50

ICD-10-CM T50.7X6A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T50.7X6A is a billable ICD-10-CM diagnosis code for underdosing of analeptics and opioid receptor 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). 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 Underdosing of drugs and medicaments, initial encounter.

Code Identity

ICD-10-CM Code
T50.7X6A
Billable Status
Yes — Valid for Submission
Code Describes
Underdosing of analeptics and opioid receptor antagonists, initial encounter
Short Description
Underdosing of analeptics and opioid receptor antag, init
Parent Code
Underdosing of analeptics and opioid receptor antagonists

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionT36-T50Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
CategoryT50Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances
This CodeT50.7X6AUnderdosing of analeptics and opioid receptor antagonists, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T50.7X6A.

There are selected codes that describe a circumstance which influences an individual's health status but not a current illness or injury, or codes that are not specific manifestations but may be due to an underlying cause. These codes are considered unacceptable as a principal diagnosis.

Coding GuidelinesGuidance

Underdosing refers to taking less of a medication than is prescribed by a provider or a manufacturer's instruction. Codes for underdosing should never be assigned as principal or first-listed codes. If a patient has a relapse or exacerbation of the medical condition for which the drug is prescribed because of the reduction in dose, then the medical condition itself should be coded.

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.

CCSR INJ029
Underdosing of drugs and medicaments, initial encounter
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Almitrine

    a respiratory stimulant that enhances respiration by acting as an agonist of peripheral chemoreceptors located on the carotid bodies. the drug increases arterial oxygen tension while decreasing arterial carbon dioxide tension in patients with chronic obstructive pulmonary disease. it may also prove useful in the treatment of nocturnal oxygen desaturation without impairing the quality of sleep.
  • Bemegride

    a cns stimulant that is used to induce convulsions in experimental animals. it has also been used as a respiratory stimulant and in the treatment of barbiturate overdose.
  • Cyclazocine

    an analgesic with mixed narcotic agonist-antagonist properties.
  • Doxapram

    a central respiratory stimulant with a brief duration of action. (from martindale, the extra pharmocopoeia, 30th ed, p1225)
  • Levallorphan

    an opioid antagonist with properties similar to those of naloxone; in addition it also possesses some agonist properties. it should be used cautiously; levallorphan reverses severe opioid-induced respiratory depression but may exacerbate respiratory depression such as that induced by alcohol or other non-opioid central depressants. (from martindale, the extra pharmacopoeia, 30th ed, p683)
  • Lobeline

    an alkaloid that has actions similar to nicotine on nicotinic cholinergic receptors but is less potent. it has been proposed for a variety of therapeutic uses including in respiratory disorders, peripheral vascular disorders, insomnia, and smoking cessation.
  • Nalorphine

    a narcotic antagonist with some agonist properties. it is an antagonist at mu opioid receptors and an agonist at kappa opioid receptors. given alone it produces a broad spectrum of unpleasant effects and it is considered to be clinically obsolete.
  • Buprenorphine, Naloxone Drug Combination

    a pharmaceutical preparation that combines buprenorphine, an opioid analgesics with naloxone, a narcotic antagonists to reduce the potential for narcotic dependence in the treatment of pain. it may also be used for opioid substitution therapy.
  • Naloxone

    a specific opiate antagonist that has no agonist activity. it is a competitive antagonist at mu, delta, and kappa opioid receptors.
  • Naltrexone

    derivative of noroxymorphone that is the n-cyclopropylmethyl congener of naloxone. it is a narcotic antagonist that is effective orally, longer lasting and more potent than naloxone, and has been proposed for the treatment of heroin addiction. the fda has approved naltrexone for the treatment of alcohol dependence.
  • Nikethamide

    a central nervous system stimulant. it was formerly used in the treatment of barbiturate overdose but is now considered to be of no value for such purposes and may be dangerous. (from martindale, the extra pharmacopoeia, 30th ed, p1229)
  • Pemoline

    a central nervous system stimulant used in fatigue and depressive states and to treat hyperkinetic disorders in children.
  • Pentylenetetrazole

    a pharmaceutical agent that displays activity as a central nervous system and respiratory stimulant. it is considered a non-competitive gamma-aminobutyric acid antagonist. pentylenetetrazole has been used experimentally to study seizure phenomenon and to identify pharmaceuticals that may control seizure susceptibility.
  • Picrotoxin

    a mixture of picrotoxinin and picrotin that is a noncompetitive antagonist at gaba-a receptors acting as a convulsant. picrotoxin blocks the gamma-aminobutyric acid-activated chloride ionophore. although it is most often used as a research tool, it has been used as a cns stimulant and an antidote in poisoning by cns depressants, especially the barbiturates.

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 T50.7X6A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
No Map There is no ICD-9 equivalent for this code.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T50.7X6AOverview

Is T50.7X6A (Underdosing of analeptics and opioid receptor antagonists) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report underdosing of analeptics and opioid receptor antagonists, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T50.7X6A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for underdosing of analeptics and opioid receptor antagonists, such as an emergency visit or first evaluation.

Can T50.7X6A be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because underdosing of analeptics and opioid receptor antagonists, initial encounter describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.

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.