ICD-10-CM G90.81: Serotonin syndrome

ICD-10-CM Diagnosis Code (2025)

Official Description for G90.81

Serotonin syndrome

Coding Notes & Guidelines for G90.81

Code First
  • poisoning due to drug or toxin, such as:
  • linezolid (T36.8X- with sixth character 1-4)
  • monoamine oxidase inhibitors (T43.1X with sixth character 1-4)
  • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.21 with sixth character 1-4)
  • selective serotonin reuptake inhibitors [SSRI] (T43.22 with sixth character 1-4)
Use Additional Code
  • code for adverse effect, if applicable, to identify drug, such as:
  • linezolid (T36.8X5)
  • monoamine oxidase inhibitors (T43.1X5)
  • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.215)
  • selective serotonin reuptake inhibitors [SSRI] (T43.225)
Use Additional Code
  • code, if applicable, to identify:
  • disseminated intravascular coagulation (D65)
  • hypertensive crisis (I16.-)
  • metabolic acidosis (E87.2-)
  • shock, not elsewhere classified (R57.-)
  • toxic encephalopathy (G92.-)
  • ventricular tachycardia (I47.2-)
Inclusion Terms

Serotonin toxicity

Parent Code (Less Specific):

G90 - Disorders of autonomic nervous system

About ICD-10-CM Code G90.81 (Serotonin syndrome)

ICD-10-CM code G90.81 is a billable or specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes. The 2025 edition of ICD-10-CM G90.81 became effective on October 1, 2024.

This page provides detailed information about G90.81 - Serotonin syndrome. It includes common terminology, coding guidelines such as "Includes," "Excludes1," and "Excludes2" notes, and information on required 7th characters. Utilizing this information correctly is essential for accurate medical coding and claims submission for conditions like Serotonin syndrome.