T42.4 — Poisoning by, adverse effect of and underdosing of benzodiazepines
T42.4 is a non-billable header ICD-10-CM code for poisoning by, adverse effect of and underdosing of benzodiazepines. It cannot be billed on its own: choose one of the more specific child codes below. This code also requires a 7th character before it is complete.
This code requires a 7th character
The appropriate 7th character is to be added to each code from category T42
- A
- initial encounter
- D
- subsequent encounter
- S
- sequela
Excludes2 inherited from the categories above T42.4
Also inherited, and the opposite of Excludes1: these conditions are not part of T42.4, but a patient can have both, so you may code both.
Other codes that can never be billed with T42.4
These codes carry an Excludes1 note pointing at T42.4. The conflict binds both ways, but ICD-10-CM only writes it down on one side — so you would not find this by reading T42.4 alone.
- T41Poisoning by, adverse effect of and underdosing of anesthetics and therapeutic gases
Risk adjustment
T42.4 does not map to an HCC and does not risk-adjust under CMS-HCC V28. That is normal — most ICD-10 codes do not. It still needs to be coded correctly; it just will not move a RAF score.
Code history
T42.4 has not changed since FY2024 — no addition, revision or deletion across the FY2024–FY2027 ICD-10-CM releases.
Code to one of these instead T42.4
1 child code. Green means billable.
Related codes at this level
Codes that share T42. If T42.4 is not quite right, the correct code is usually one of these.
- T42.0Poisoning by, adverse effect of and underdosing of hydantoin derivatives
- T42.1Poisoning by, adverse effect of and underdosing of iminostilbenes
- T42.2Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
- T42.3Poisoning by, adverse effect of and underdosing of barbiturates
- T42.5Poisoning by, adverse effect of and underdosing of mixed antiepileptics
- T42.6Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
- T42.7Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs
- T42.8Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
Questions about T42.4
- Is T42.4 a billable ICD-10-CM code?
- No. T42.4 is a non-billable header code. Code to a higher level of specificity using one of its child codes.
- Where does T42.4 sit in the tabular list?
- Injury, poisoning and certain other consequences of external causes (S00-T88), in the block Poisoning by, adverse effects of and underdosing of drugs, medicaments and biological substances (T36-T50).