T43.636Header code — not billable
Underdosing of methylphenidate
- Chapter
- 19. Injury, poisoning and certain other consequences of external causes
- Category
- T43
- Effective date
- October 1, 2026
Related codes in category T43
T43Psychotropic drugs, not elsewhere classifiedT43.0Tricyclic and tetracyclic antidepressantsT43.01Tricyclic antidepressantsT43.011Poisoning by tricyclic antidepressants, accidentalT43.011APoisoning by tricyclic antidepressants, accidental, initYesT43.011DPoisoning by tricyclic antidepressants, accidental, subsYesT43.011SPoisoning by tricyclic antidepressants, accidental, sequelaYesT43.012Poisoning by tricyclic antidepressants, self-harmT43.012APoisoning by tricyclic antidepressants, self-harm, initYesT43.012DPoisoning by tricyclic antidepressants, self-harm, subsYesT43.012SPoisoning by tricyclic antidepressants, self-harm, sequelaYesT43.013Poisoning by tricyclic antidepressants, assault
Frequently asked questions
What is ICD-10 code T43.636?
T43.636 is an ICD-10-CM diagnosis code for Underdosing of methylphenidate.
Is T43.636 a billable code?
No. T43.636 is a category/header code, not billable on its own — use one of its more specific child codes instead.
What ICD-10-CM chapter is T43.636 in?
T43.636 falls under Chapter 19: Injury, poisoning and certain other consequences of external causes.
When did T43.636 become effective?
T43.636 has been effective since October 1, 2026, per the CMS/CDC ICD-10-CM annual release.
What other codes are related to T43.636?
T43.636 belongs to category T43, which includes 12 other codes — see the related codes list on this page.
ICD-10-CM data maintained by CDC/CMS (public domain). Always verify codes with authoritative sources before making coding or billing decisions.