2026 ICD-10-CM Diagnosis Code T40.495SAdverse effect of other synthetic narcotics, sequela
T40.495S is a billable ICD-10-CM diagnosis code for adverse effect of other synthetic narcotics, sequela. The 7th character S marks it as a sequela code, which reports a problem that remains after the original condition has resolved. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 922 through 923. The code is not accepted as a principal diagnosis by the Medicare Code Editor and exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Mental and substance use disorders; sequela; and Poisoning/toxic effect/adverse effects/underdosing, sequela.
Code Identity
Code Classification
Code EditsBilling
Medicare Code Editor checks that affect claim validity for T40.495S.
Present on Admission (POA)Billing
T40.495S is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Buprenorphine adverse reaction
- Dextromoramide adverse reaction
- Dextropropoxyphene adverse reaction
- Dipipanone adverse reaction
- Levorphanol adverse reaction
- Meperidine analog adverse reaction
- Morphinan opioid adverse reaction
- Nalbuphine adverse reaction
- Pentazocine adverse reaction
- Pethidine adverse reaction
- Phenazocine adverse reaction
- Phenoperidine adverse reaction
- Propionic acid derivative 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.
Clinical InformationClinical
Alphaprodine
an opioid analgesic chemically related to and with an action resembling that of meperidine, but more rapid in onset and of shorter duration. it has been used in obstetrics, as pre-operative medication, for minor surgical procedures, and for dental procedures. (from martindale, the extra pharmacopoeia, 30th ed, p1067)Buprenorphine
a derivative of the opioid alkaloid thebaine that is a more potent and longer lasting analgesic than morphine. it appears to act as a partial agonist at mu and kappa opioid receptors and as an antagonist at delta receptors. the lack of delta-agonist activity has been suggested to account for the observation that buprenorphine tolerance may not develop with chronic use.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.Butorphanol
a synthetic morphinan analgesic with narcotic antagonist action. it is used in the management of severe pain.Dextropropoxyphene
a narcotic analgesic structurally related to methadone. only the dextro-isomer has an analgesic effect; the levo-isomer appears to exert an antitussive effect.Levopropoxyphene
a propionate derivative that is used to suppress coughing.Levorphanol
a narcotic analgesic that may be habit-forming. it is nearly as effective orally as by injection.Meperidine
a narcotic analgesic that can be used for the relief of most types of moderate to severe pain, including postoperative pain and the pain of labor. prolonged use may lead to dependence of the morphine type; withdrawal symptoms appear more rapidly than with morphine and are of shorter duration.Nalbuphine
a narcotic used as a pain medication. it appears to be an agonist at kappa receptors and an antagonist or partial agonist at mu receptors.Pentazocine
the first mixed agonist-antagonist analgesic to be marketed. it is an agonist at the kappa and sigma opioid receptors and has a weak antagonist action at the mu receptor. (from ama drug evaluations annual, 1991, p97)Phenazocine
an opioid analgesic with actions and uses similar to morphine. (from martindale, the extra pharmacopoeia, 30th ed, p1095)
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.
Code History & ChangesHistory
Replacement T40.495S replaces the following previously assigned code(s):
- T40.4X5S - Adverse effect of other synthetic narcotics, sequela
Questions About T40.495SOverview
Is T40.495S (Adverse effect of other synthetic narcotics) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of other synthetic narcotics, sequela on HIPAA-covered claims from October 1, 2025 through September 30, 2026.
What does the 7th character S in T40.495S mean?
The final character S makes this a sequela code: it reports a lingering problem that remains after the adverse effect of other synthetic narcotics itself has resolved, not the original event.
What MS-DRG does T40.495S group to?
On inpatient claims, adverse effect of other synthetic narcotics, sequela maps to MS-DRG 922, 923, with relative weights from 1.0177 to 1.7494 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T40.495S be a principal diagnosis?
No. The Medicare Code Editor rejects this code as a principal diagnosis because adverse effect of other synthetic narcotics, sequela describes a circumstance that influences health status rather than a current illness. Report it as a secondary diagnosis.
Is T40.495S exempt from POA reporting?
Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for adverse effect of other synthetic narcotics, sequela on inpatient claims.
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.
