2025 ICD-10-CM Diagnosis Code G90.81
Serotonin syndrome
- ICD-10-CM Code:
- G90.81
- ICD-10 Code for:
- Serotonin syndrome
- Is Billable?
- Yes - Valid for Submission
- Code Navigator:
G90.81 is a billable diagnosis code used to specify a medical diagnosis of serotonin syndrome. The code is valid during the current fiscal year for the submission of HIPAA-covered transactions from October 01, 2024 through September 30, 2025.
Approximate Synonyms
The following list of clinical terms are approximate synonyms, alternative descriptions, or common phrases that might be used by patients, healthcare providers, or medical coders to describe the same condition. These synonyms and related diagnosis terms are often used when searching for an ICD-10 code, especially when the exact medical terminology is unclear. Whether you're looking for lay terms, similar diagnosis names, or common language alternatives, this list can help guide you to the correct ICD-10 classification.
- Serotonin syndrome
Clinical Information
Serotonin Syndrome
an adverse drug interaction characterized by altered mental status, autonomic dysfunction, and neuromuscular abnormalities. it is most frequently caused by use of both serotonin reuptake inhibitors and monoamine oxidase inhibitors, leading to excess serotonin availability in the cns at the serotonin 1a receptor.
New 2025 ICD-10-CM Code
G90.81 is new to ICD-10-CM code set for the FY 2025, effective October 1, 2024. The National Center for Health Statistics (NCHS) has published an update to the ICD-10-CM diagnosis codes which became effective October 1, 2024. This is a new and revised code for the FY 2025 (October 1, 2024 - September 30, 2025).
Tabular List of Diseases and Injuries
The following annotation back-references are applicable to this diagnosis code. The Tabular List of Diseases and Injuries is a list of ICD-10-CM codes, organized "head to toe" into chapters and sections with coding notes and guidance for inclusions, exclusions, descriptions and more.
Inclusion Terms
Inclusion TermsThese terms are the conditions for which that code is to be used. The terms may be synonyms of the code title, or, in the case of "other specified" codes, the terms are a list of the various conditions assigned to that code. The inclusion terms are not necessarily exhaustive. Additional terms found only in the Alphabetic Index may also be assigned to a code.
- Serotonin toxicity
Code First
Code FirstCertain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. For such conditions, the ICD-10-CM has a coding convention that requires the underlying condition be sequenced first followed by the manifestation. Wherever such a combination exists, there is a "use additional code" note at the etiology code, and a "code first" note at the manifestation code. These instructional notes indicate the proper sequencing order of the codes, etiology followed by manifestation.
- poisoning due to drug or toxin, such as:
- linezolid T36.8X
- monoamine oxidase inhibitors T43.1X
- selective serotonin and norepinephrine reuptake inhibitors SSNRI T43.21
- selective serotonin reuptake inhibitors SSRI T43.22
Use Additional Code
Use Additional CodeThe “use additional code” indicates that a secondary code could be used to further specify the patient’s condition. This note is not mandatory and is only used if enough information is available to assign an additional code.
Index to Diseases and Injuries References
The following annotation back-references for this diagnosis code are found in the injuries and diseases index. The Index to Diseases and Injuries is an alphabetical listing of medical terms, with each term mapped to one or more ICD-10-CM code(s).
Replacement Code
G9081 replaces the following previously assigned ICD-10-CM code(s):
- G90.8 - Other disorders of autonomic nervous system
