ICD-10 T42.6
Non-Billable HeaderPoisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
About ICD-10-CM T42.6
ICD-10-CM code T42.6 represents Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs. This is a non-billable header code in the Injury, Poisoning, and External Causes chapter (block T42). The 2026 edition of ICD-10-CM T42.6 became effective on October 1, 2025. Non-billable codes cannot be used as a primary or secondary diagnosis on a claim, use a more specific child code instead.
Coding Tips for T42.6
Specialist guidance from the PayerReady Medical Coding Team. Specificity warnings, HCC capture rules, sequencing notes.
Injury codes require a 7th character: A (initial encounter, active treatment), D (subsequent, healing/recovery), S (sequela, late effect of original injury). Codes with fewer than 6 characters need the placeholder X to bring them to 6 characters before adding the 7th. Wrong or missing 7th character is the #1 cause of injury claim denials.
Inclusion Terms / Approximate Synonyms
Clinical terms and conditions classified under T42.6. Per CMS ICD-10-CM Tabular 2026.
- Poisoning by, adverse effect of and underdosing of methaqualone
- Poisoning by, adverse effect of and underdosing of valproic acid
Type 1 Excludes
Pure excludes, these codes can never be coded together with T42.6. The conditions are mutually exclusive (e.g., congenital vs acquired forms).
- poisoning by, adverse effect of and underdosing of carbamazepine (T42.1-)
Medicare LCD Coverage for T42.6
Local Coverage Determinations (LCDs) from CMS MACs that list T42.6 as a covered diagnosis.
This doesn't mean the code isn't covered, it means no MAC has issued a Local Coverage Determination naming this specific code. Coverage may still apply under National Coverage Determinations or general medical-necessity rules.
Commercial Payer Coverage
Coverage policies from major commercial payers referencing T42.6.
Our payer policy database covers Aetna, Cigna, Anthem, BCBS, Humana, and Medicare Advantage plans, but T42.6 doesn't currently appear in any indexed policy. The code may still be covered under standard plan benefits.
CPT Codes Commonly Billed with T42.6
Procedures frequently paired with this diagnosis based on PayerReady's Dx↔Px linkage data.
We don't have CPT pairings indexed for this specific code yet. Use the CPT search above to find common procedures, or check your payer's published medical policy for code-specific guidance.
Codes Adjacent To T42.6
Other codes in section T36-T50 (Poisoning by, adverse effect of and underdosing of drugs, medicaments and biological substances).
ICD-10 T42.6, Billing FAQ
Is ICD-10 code T42.6 billable? +
No, T42.6 is a non-billable header code. Use a more specific child code from block T42 when submitting claims.
What other names or terms map to T42.6? +
ICD-10 T42.6 includes: Poisoning by, adverse effect of and underdosing of methaqualone; Poisoning by, adverse effect of and underdosing of valproic acid.
What codes are Type 1 Excludes for T42.6? +
Type 1 Excludes (never code together with T42.6): poisoning by, adverse effect of and underdosing of carbamazepine (T42.1-)
Get the full PayerReady toolkit
Free access to CPT/ICD-10 lookup, denial appeals, fee comparator, and claim auditing with credentialing enrollment.
Start free →Run this code through our claim audit tool
Check NCCI bundling, MUE limits, and modifier logic before submission.
Try the auditor →Did this page help?
Quick signal so we know what to improve.
If you want a code reference page that doesn't exist yet, email coding@payerready.com.
Tell us what's missing or wrong: coding@payerready.com. We respond within 5 business days.
Reviewed by the PayerReady Medical Coding Team
Verified against the CMS 2026 code set on May 31, 2026.
Powered by 11K CPT · 98K ICD-10 · 860K MPFS rates · 4.5M NCCI edits · 9.5M NPIs. Our data methodology · About our coding team