2026 ICD-10-CM Diagnosis Code T40.715AAdverse effect of cannabis, initial encounter

ICD-10-CM Codes›S00–T88›T36-T50›T40

ICD-10-CM T40.715A
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

T40.715A is a billable ICD-10-CM diagnosis code for adverse effect of cannabis, 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 adverse reaction caused by synthetic cannabinoid. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter; and Cannabis-related disorders.

Code Identity

ICD-10-CM Code
T40.715A
Billable Status
Yes — Valid for Submission
Code Describes
Adverse effect of cannabis, initial encounter
Short Description
Adverse effect of cannabis, initial encounter
Same as the full description in the CMS dataset.
Parent Code
T40.715
Adverse effect of cannabis

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
CategoryT40Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
This CodeT40.715AAdverse effect of cannabis, initial encounter

Code EditsBilling

Medicare Code Editor checks that affect claim validity for T40.715A.

Unacceptable principal diagnosis
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.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Adverse reaction caused by synthetic cannabinoid
  • Adverse reaction to cannabis
  • Adverse reaction to hallucinogen
  • Nabilone 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 narcotics and psychodysleptics [hallucinogens] (T40). 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 INJ028
Adverse effects of drugs and medicaments, initial encounter
Default principal diagnosis: inpatient No · outpatient Yes
CCSR MBD019
Cannabis-related disorders
Default principal diagnosis: inpatient No · outpatient No

Clinical InformationClinical

  • Cannabinol

    a physiologically inactive constituent of cannabis sativa l.

  • Dronabinol

    a psychoactive compound extracted from the resin of cannabis sativa (marihuana, hashish). the isomer delta-9-tetrahydrocannabinol (thc) is considered the most active form, producing characteristic mood and perceptual changes associated with this compound.

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.

SubstanceAccidentalSelf-harmAssaultUndeter­minedAdverse
Effect		Under­dosing
Afghanistan blackT40.711T40.712T40.713T40.714T40.715T40.716
BhangT40.711T40.712T40.713T40.714T40.715T40.716
CannabinolT40.711T40.712T40.713T40.714T40.715T40.716
Cannabis (derivatives)T40.711T40.712T40.713T40.714T40.715T40.716
DronabinolT40.711T40.712T40.713T40.714T40.715T40.716
GanjaT40.711T40.712T40.713T40.714T40.715T40.716
HashishT40.711T40.712T40.713T40.714T40.715T40.716
IndianT40.711T40.712T40.713T40.714T40.715T40.716
Indian::hempT40.711T40.712T40.713T40.714T40.715T40.716
Indian::tobaccoT40.711T40.712T40.713T40.714T40.715T40.716
Lebanese redT40.711T40.712T40.713T40.714T40.715T40.716
MarihuanaT40.711T40.712T40.713T40.714T40.715T40.716
MarijuanaT40.711T40.712T40.713T40.714T40.715T40.716
NabiloneT40.711T40.712T40.713T40.714T40.715T40.716
PotT40.711T40.712T40.713T40.714T40.715T40.716
TetrahydrocannabinolT40.711T40.712T40.713T40.714T40.715T40.716
THCT40.711T40.712T40.713T40.714T40.715T40.716

Code History & ChangesHistory

Replacement T40.715A replaces the following previously assigned code(s):

  • T40.7X5A - Adverse effect of cannabis (derivatives), initial encounter
FY 2022AddedAdded to the ICD-10-CM code setEffective October 1, 2021.
FY 2023–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About T40.715AOverview

Is T40.715A (Adverse effect of cannabis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of cannabis, initial encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character A in T40.715A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of cannabis, such as an emergency visit or first evaluation.

What MS-DRG does T40.715A group to?

On inpatient claims, adverse effect of cannabis, 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 T40.715A be a principal diagnosis?

No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of cannabis, 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.