2026 ICD-10-CM Diagnosis Code G44.40Drug-induced headache, not elsewhere classified, not intractable

ICD-10-CM Codes›G00–G99›G40-G47›G44

ICD-10-CM G44.40
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

G44.40 is a billable ICD-10-CM diagnosis code for drug-induced headache, not elsewhere classified, not intractable. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 102 through 103. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Drug induced or toxic related condition and Headache; including migraine.

Code Identity

ICD-10-CM Code
G44.40
Billable Status
Yes — Valid for Submission
Code Describes
Drug-induced headache, not elsewhere classified, not intractable
Short Description
Drug-induced headache, NEC, not intractable
Parent Code
G44.4
Drug-induced headache, not elsewhere classified

Code Classification

ChapterG00–G99Diseases of the nervous system
SectionG40-G47Episodic and paroxysmal disorders
CategoryG44Other headache syndromes
This CodeG44.40Drug-induced headache, not elsewhere classified, not intractable

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Analgesic overuse headache
  • Drug withdrawal headache
  • Headache associated with substance abuse or withdrawal
  • Headache caused by drug
  • Headache caused by oral contraceptive pill
  • Headache due to caffeine withdrawal syndrome
  • Medication overuse headache
  • Medication overuse headache caused by ergotamine

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Headache
      • drug-induced NEC
    • Headache
      • drug-induced NEC
        • not intractable
    • Headache
      • medication overuse
    • Headache
      • medication overuse
        • not intractable
    • Headache
      • rebound
    • Headache
      • rebound
        • not intractable

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ030
Drug induced or toxic related condition
Default principal diagnosis: inpatient Yes · outpatient Yes
CCSR NVS010
Headache; including migraine
Default principal diagnosis: inpatient No · outpatient No

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 G44.40 to ICD-9-CMHistory

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

ICD-9-CM
339.3 Drug induce headache NEC
Approximate The match is approximate rather than exact.

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 G44.40Overview

Is G44.40 (Drug-induced headache, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report drug-induced headache, not elsewhere classified, not intractable on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does G44.40 group to?

When drug-induced headache, not elsewhere classified, not intractable is the principal diagnosis on an inpatient stay, it groups to MS-DRG 102, 103, with relative weights from 0.8363 to 1.1209 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of G44.40?

Under the General Equivalence Mappings, drug-induced headache, not elsewhere classified, not intractable converts to ICD-9-CM 339.3 (drug induce headache NEC). 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.