ICD-10-CM 2027
ICD-10 code for Drowsiness
From the official ICD-10-CM alphabetic index entry “Drowsiness”. Page updated September 29, 2026.
About coding Drowsiness
The ICD-10-CM code for Drowsiness is R40.0 (Somnolence).
Within R40 (Somnolence, stupor and coma), R40.0 is specifically for Somnolence. Related codes cover stupor (R40.1), coma (R40.2), persistent vegetative state (R40.3) and transient alteration of awareness (R40.4).
Don't report R40.0 together with the conditions in its Excludes1 note: coma (R40.2-).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Don't confuse with (Excludes1 for R40.0)
- coma (R40.2-)
Common questions about Drowsiness ICD-10 codes
What is the ICD-10 code for Drowsiness?
- R40.0 — Somnolence.
Is R40.0 billable?
- Yes. R40.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can R40.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict R40.0 as a principal diagnosis.
Is R40.0 a CC or MCC?
- No. R40.0 is neither a CC nor an MCC under MS-DRG v44.0.