T43.634 (Poisoning by methylphenidate, undetermined) compared with T43.635 (Adverse effect of methylphenidate), from the official CMS tabular data. T43.634 and T43.635 code the same substance (Methylphenidate) with a different intent.
Same substance, different circumstance of exposure.
Same substance — adverse effect (Methylphenidate)
Accidental poisoning, intentional self-harm, assault, undetermined intent, adverse effect and underdosing are mutually exclusive columns — exactly one applies to a given encounter.
Source: CMS Table of Drugs and Chemicals
Same substance, different intent. T43.634 and T43.635 code the same substance (Methylphenidate) with a different circumstance of exposure.
From the CMS Table of Drugs and Chemicals: accidental poisoning, intentional self-harm, assault, undetermined intent, adverse effect and underdosing are mutually exclusive columns — only one of them applies to a given encounter.
| T43.634Poisoning by methylphenidate, undetermined | T43.635Adverse effect of methylphenidate | |
|---|---|---|
| Billing status | Non-billable header | Non-billable header |
| Classification | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) | S00-T88 — Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) |
| Definition | Poisoning by methylphenidate, undetermined is a non-billable ICD-10-CM category code (T43.634). | Adverse effect of methylphenidate is a non-billable ICD-10-CM category code (T43.635). |
| 7th character | The appropriate 7th character is to be added to each code from category T43 | The appropriate 7th character is to be added to each code from category T43 |
| Includes | adverse effect of correct substance properly administered poisoning by overdose of substance poisoning by wrong substance given or taken in error underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed | adverse effect of correct substance properly administered poisoning by overdose of substance poisoning by wrong substance given or taken in error underdosing by (inadvertently) (deliberately) taking less substance than prescribed or instructed |
| Use additional code | code(s) to specify: manifestations of poisoning underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9) | code(s) to specify: manifestations of poisoning underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9) |
| Code first | , for adverse effects, the nature of the adverse effect, such as: adverse effect NOS (T88.7) | , for adverse effects, the nature of the adverse effect, such as: adverse effect NOS (T88.7) |
Derived from the official CMS ICD-10-CM tabular data (FY2026). Not billing advice; verify sequencing rules for the encounter. All data sources