Version 2024

2024 ICD-10-CM Diagnosis Code T40.4

Poisoning by, adverse effect of and underdosing of other synthetic narcotics

ICD-10-CM Code:
T40.4
ICD-10 Code for:
Synthetic narcotics
Is Billable?
Not Valid for Submission
Code Navigator:

Code Classification

  • Injury, poisoning and certain other consequences of external causes
    (S00–T88)
    • Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances
      (T36-T50)
      • Poisoning by, adverse effect of and underdosing of narcotics and psychodysleptics [hallucinogens]
        (T40)

T40.4 is a non-specific and non-billable diagnosis code code, consider using a code with a higher level of specificity for a diagnosis of poisoning by, adverse effect of and underdosing of other synthetic narcotics. The code is not specific and is NOT valid for the year 2024 for the submission of HIPAA-covered transactions. Category or Header define the heading of a category of codes that may be further subdivided by the use of 4th, 5th, 6th or 7th characters.

Specific Coding Applicable to Synthetic narcotics

Non-specific codes like T40.4 require more digits to indicate the appropriate level of specificity. Consider using any of the following ICD-10-CM codes with a higher level of specificity when coding for synthetic narcotics:

  • T40.41 for Poisoning by, adverse effect of and underdosing of fentanyl or fentanyl analogs - NON-BILLABLE CODE

  • T40.411 for Poisoning by fentanyl or fentanyl analogs, accidental (unintentional) - NON-BILLABLE CODE

  • Use T40.411A for initial encounter - BILLABLE CODE

  • Use T40.411D for subsequent encounter - BILLABLE CODE

  • Use T40.411S for sequela - BILLABLE CODE

  • T40.412 for Poisoning by fentanyl or fentanyl analogs, intentional self-harm - NON-BILLABLE CODE

  • Use T40.412A for initial encounter - BILLABLE CODE

  • Use T40.412D for subsequent encounter - BILLABLE CODE

  • Use T40.412S for sequela - BILLABLE CODE

  • T40.413 for Poisoning by fentanyl or fentanyl analogs, assault - NON-BILLABLE CODE

  • Use T40.413A for initial encounter - BILLABLE CODE

  • Use T40.413D for subsequent encounter - BILLABLE CODE

  • Use T40.413S for sequela - BILLABLE CODE

  • T40.414 for Poisoning by fentanyl or fentanyl analogs, undetermined - NON-BILLABLE CODE

  • Use T40.414A for initial encounter - BILLABLE CODE

  • Use T40.414D for subsequent encounter - BILLABLE CODE

  • Use T40.414S for sequela - BILLABLE CODE

  • T40.415 for Adverse effect of fentanyl or fentanyl analogs - NON-BILLABLE CODE

  • Use T40.415A for initial encounter - BILLABLE CODE

  • Use T40.415D for subsequent encounter - BILLABLE CODE

  • Use T40.415S for sequela - BILLABLE CODE

  • T40.416 for Underdosing of fentanyl or fentanyl analogs - NON-BILLABLE CODE

  • Use T40.416A for initial encounter - BILLABLE CODE

  • Use T40.416D for subsequent encounter - BILLABLE CODE

  • Use T40.416S for sequela - BILLABLE CODE

  • T40.42 for Poisoning by, adverse effect of and underdosing of tramadol - NON-BILLABLE CODE

  • T40.421 for Poisoning by tramadol, accidental (unintentional) - NON-BILLABLE CODE

  • Use T40.421A for initial encounter - BILLABLE CODE

  • Use T40.421D for subsequent encounter - BILLABLE CODE

  • Use T40.421S for sequela - BILLABLE CODE

  • T40.422 for Poisoning by tramadol, intentional self-harm - NON-BILLABLE CODE

  • Use T40.422A for initial encounter - BILLABLE CODE

  • Use T40.422D for subsequent encounter - BILLABLE CODE

  • Use T40.422S for sequela - BILLABLE CODE

  • T40.423 for Poisoning by tramadol, assault - NON-BILLABLE CODE

  • Use T40.423A for initial encounter - BILLABLE CODE

  • Use T40.423D for subsequent encounter - BILLABLE CODE

  • Use T40.423S for sequela - BILLABLE CODE

  • T40.424 for Poisoning by tramadol, undetermined - NON-BILLABLE CODE

  • Use T40.424A for initial encounter - BILLABLE CODE

  • Use T40.424D for subsequent encounter - BILLABLE CODE

  • Use T40.424S for sequela - BILLABLE CODE

  • T40.425 for Adverse effect of tramadol - NON-BILLABLE CODE

  • Use T40.425A for initial encounter - BILLABLE CODE

  • Use T40.425D for subsequent encounter - BILLABLE CODE

  • Use T40.425S for sequela - BILLABLE CODE

  • T40.426 for Underdosing of tramadol - NON-BILLABLE CODE

  • Use T40.426A for initial encounter - BILLABLE CODE

  • Use T40.426D for subsequent encounter - BILLABLE CODE

  • Use T40.426S for sequela - BILLABLE CODE

  • T40.49 for Poisoning by, adverse effect of and underdosing of other synthetic narcotics - NON-BILLABLE CODE

  • T40.491 for Poisoning by other synthetic narcotics, accidental (unintentional) - NON-BILLABLE CODE

  • Use T40.491A for initial encounter - BILLABLE CODE

  • Use T40.491D for subsequent encounter - BILLABLE CODE

  • Use T40.491S for sequela - BILLABLE CODE

  • T40.492 for Poisoning by other synthetic narcotics, intentional self-harm - NON-BILLABLE CODE

  • Use T40.492A for initial encounter - BILLABLE CODE

  • Use T40.492D for subsequent encounter - BILLABLE CODE

  • Use T40.492S for sequela - BILLABLE CODE

  • T40.493 for Poisoning by other synthetic narcotics, assault - NON-BILLABLE CODE

  • Use T40.493A for initial encounter - BILLABLE CODE

  • Use T40.493D for subsequent encounter - BILLABLE CODE

  • Use T40.493S for sequela - BILLABLE CODE

  • T40.494 for Poisoning by other synthetic narcotics, undetermined - NON-BILLABLE CODE

  • Use T40.494A for initial encounter - BILLABLE CODE

  • Use T40.494D for subsequent encounter - BILLABLE CODE

  • Use T40.494S for sequela - BILLABLE CODE

  • T40.495 for Adverse effect of other synthetic narcotics - NON-BILLABLE CODE

  • Use T40.495A for initial encounter - BILLABLE CODE

  • Use T40.495D for subsequent encounter - BILLABLE CODE

  • Use T40.495S for sequela - BILLABLE CODE

  • T40.496 for Underdosing of other synthetic narcotics - NON-BILLABLE CODE

  • Use T40.496A for initial encounter - BILLABLE CODE

  • Use T40.496D for subsequent encounter - BILLABLE CODE

  • Use T40.496S for sequela - BILLABLE CODE

Coding Guidelines

When coding a poisoning or reaction to the improper use of a medication (e.g., overdose, wrong substance given or taken in error, wrong route of administration), first assign the appropriate code from categories T36-T50. The poisoning codes have an associated intent as their 5th or 6th character (accidental, intentional self-harm, assault and undetermined. If the intent of the poisoning is unknown or unspecified, code the intent as accidental intent. The undetermined intent is only for use if the documentation in the record specifies that the intent cannot be determined. Use additional code(s) for all manifestations of poisonings.

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 aplicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Patient Education


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.

What is a drug interaction?

A drug interaction is a change in the way a drug acts in the body when taken with certain other drugs, foods, or supplements or when taken while you have certain medical conditions. Examples include:

  • Two drugs, such as aspirin and blood thinners
  • Drugs and food, such as statins and grapefruit
  • Drugs and supplements, such as gingko and blood thinners
  • Drugs and medical conditions, such as aspirin and peptic ulcers

Interactions could cause a drug to be more or less effective, cause side effects, or change the way one or both drugs work.

What are side effects?

Side effects are unwanted, usually unpleasant, effects caused by medicines. Most are mild, such as a stomachache, dry mouth, or drowsiness, and go away after you stop taking the medicine. Others can be more serious. Sometimes a drug can interact with a disease that you have and cause a side effect. For example, if you have a heart condition, certain decongestants can cause you to have a rapid heartbeat.

What are drug allergies?

Drug allergies are another type of reaction. They can range from mild to life-threatening. Skin reactions, such as hives and rashes, are the most common type. Anaphylaxis, a serious allergic reaction, is less common.

How can I stay safe when taking medicines?

When you start a new prescription or over-the-counter medicine, make sure you understand how to take it correctly. Know which other medicines, foods, and supplements you need to avoid. Always talk to your health care provider or pharmacist if you have questions about your medicines.


[Learn More in MedlinePlus]

Code History

  • FY 2024 - No Change, effective from 10/1/2023 through 9/30/2024
  • FY 2023 - No Change, effective from 10/1/2022 through 9/30/2023
  • FY 2022 - No Change, effective from 10/1/2021 through 9/30/2022
  • FY 2021 - No Change, effective from 10/1/2020 through 9/30/2021
  • FY 2020 - No Change, effective from 10/1/2019 through 9/30/2020
  • FY 2019 - No Change, effective from 10/1/2018 through 9/30/2019
  • FY 2018 - No Change, effective from 10/1/2017 through 9/30/2018
  • FY 2017 - No Change, effective from 10/1/2016 through 9/30/2017
  • FY 2016 - New Code, effective from 10/1/2015 through 9/30/2016. This was the first year ICD-10-CM was implemented into the HIPAA code set.