DxCodebookFY2027 · Oct 1, 2026 – Sep 30, 2027

Category · FY2027

T42 Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs

  • Header · not billable
  • Codes take a 7th character

T42 is not billable. The category heads 162 billable codes in FY2027, grouped under 9 subdivisions. Its codes take a 7th character, so none is complete with fewer than 7 characters.

Billable codes
162
Subdivisions
9
CC / MCC codes
0 / 0
HCC V28 codes
9
New FY2027
0
Index entries
0

Codes in T42

  1. T42.0
    Poisoning by, adverse effect of and underdosing of hydantoin derivatives
    Header
  2. T42.0X
    Poisoning by, adverse effect of and underdosing of hydantoin derivatives
    Header
  3. T42.0X1
    Poisoning by hydantoin derivatives, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by hydantoin derivatives NOS
  4. T42.0X2
    Poisoning by hydantoin derivatives, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  5. T42.0X3
    Poisoning by hydantoin derivatives, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  6. T42.0X4
    Poisoning by hydantoin derivatives, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  7. T42.0X5
    Adverse effect of hydantoin derivatives +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  8. T42.0X6
    Underdosing of hydantoin derivatives +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  9. T42.1
    Poisoning by, adverse effect of and underdosing of iminostilbenes
    Header
    Inclusion terms 1

    Inclusion terms

    • Poisoning by, adverse effect of and underdosing of carbamazepine
  10. T42.1X
    Poisoning by, adverse effect of and underdosing of iminostilbenes
    Header
  11. T42.1X1
    Poisoning by iminostilbenes, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by iminostilbenes NOS
  12. T42.1X2
    Poisoning by iminostilbenes, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  13. T42.1X3
    Poisoning by iminostilbenes, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  14. T42.1X4
    Poisoning by iminostilbenes, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  15. T42.1X5
    Adverse effect of iminostilbenes +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  16. T42.1X6
    Underdosing of iminostilbenes +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  17. T42.2
    Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
    Header
  18. T42.2X
    Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones
    Header
  19. T42.2X1
    Poisoning by succinimides and oxazolidinediones, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by succinimides and oxazolidinediones NOS
  20. T42.2X2
    Poisoning by succinimides and oxazolidinediones, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  21. T42.2X3
    Poisoning by succinimides and oxazolidinediones, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  22. T42.2X4
    Poisoning by succinimides and oxazolidinediones, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  23. T42.2X5
    Adverse effect of succinimides and oxazolidinediones +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  24. T42.2X6
    Underdosing of succinimides and oxazolidinediones +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  25. T42.3
    Poisoning by, adverse effect of and underdosing of barbiturates
    Header
    Excludes1 1

    Excludes1

    • poisoning by, adverse effect of and underdosing of thiobarbiturates (T41.1-) T41.1
  26. T42.3X
    Poisoning by, adverse effect of and underdosing of barbiturates
    Header
  27. T42.3X1
    Poisoning by barbiturates, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by barbiturates NOS
  28. T42.3X2
    Poisoning by barbiturates, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  29. T42.3X3
    Poisoning by barbiturates, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  30. T42.3X4
    Poisoning by barbiturates, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  31. T42.3X5
    Adverse effect of barbiturates +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  32. T42.3X6
    Underdosing of barbiturates +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  33. T42.4
    Poisoning by, adverse effect of and underdosing of benzodiazepines
    Header
  34. T42.4X
    Poisoning by, adverse effect of and underdosing of benzodiazepines
    Header
  35. T42.4X1
    Poisoning by benzodiazepines, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by benzodiazepines NOS
  36. T42.4X2
    Poisoning by benzodiazepines, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  37. T42.4X3
    Poisoning by benzodiazepines, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  38. T42.4X4
    Poisoning by benzodiazepines, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  39. T42.4X5
    Adverse effect of benzodiazepines +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  40. T42.4X6
    Underdosing of benzodiazepines +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  41. T42.5
    Poisoning by, adverse effect of and underdosing of mixed antiepileptics
    Header
  42. T42.5X
    Poisoning by, adverse effect of and underdosing of antiepileptics
    Header
  43. T42.5X1
    Poisoning by mixed antiepileptics, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by mixed antiepileptics NOS
  44. T42.5X2
    Poisoning by mixed antiepileptics, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  45. T42.5X3
    Poisoning by mixed antiepileptics, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  46. T42.5X4
    Poisoning by mixed antiepileptics, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  47. T42.5X5
    Adverse effect of mixed antiepileptics +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  48. T42.5X6
    Underdosing of mixed antiepileptics +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  49. T42.6
    Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
    Header
    Inclusion terms 2, Excludes1 1

    Inclusion terms

    • Poisoning by, adverse effect of and underdosing of methaqualone
    • Poisoning by, adverse effect of and underdosing of valproic acid

    Excludes1

    • poisoning by, adverse effect of and underdosing of carbamazepine (T42.1-) T42.1
  50. T42.6X
    Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs
    Header
  51. T42.6X1
    Poisoning by other antiepileptic and sedative-hypnotic drugs, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by other antiepileptic and sedative-hypnotic drugs NOS
  52. T42.6X2
    Poisoning by other antiepileptic and sedative-hypnotic drugs, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  53. T42.6X3
    Poisoning by other antiepileptic and sedative-hypnotic drugs, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  54. T42.6X4
    Poisoning by other antiepileptic and sedative-hypnotic drugs, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  55. T42.6X5
    Adverse effect of other antiepileptic and sedative-hypnotic drugs +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  56. T42.6X6
    Underdosing of other antiepileptic and sedative-hypnotic drugs +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  57. T42.7
    Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs
    Header
  58. T42.71
    Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by antiepileptic and sedative-hypnotic drugs NOS
  59. T42.72
    Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  60. T42.73
    Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  61. T42.74
    Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  62. T42.75
    Adverse effect of unspecified antiepileptic and sedative-hypnotic drugs +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  63. T42.76
    Underdosing of unspecified antiepileptic and sedative-hypnotic drugs +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  64. T42.8
    Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
    Header
    Inclusion terms 1

    Inclusion terms

    • Poisoning by, adverse effect of and underdosing of amantadine
  65. T42.8X
    Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants
    Header
  66. T42.8X1
    Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, accidental (unintentional) +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
    Inclusion terms 1

    Inclusion terms

    • Poisoning by antiparkinsonism drugs and other central muscle-tone depressants NOS
  67. T42.8X2
    Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, intentional self-harm +7th: A D S
    Needs 7th character155 (some 7th characters)Exempt: 2 of 3 7th characters
  68. T42.8X3
    Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, assault +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  69. T42.8X4
    Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  70. T42.8X5
    Adverse effect of antiparkinsonism drugs and other central muscle-tone depressants +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters
  71. T42.8X6
    Underdosing of antiparkinsonism drugs and other central muscle-tone depressants +7th: A D S
    Needs 7th characterExempt: 2 of 3 7th characters

Sources of each column. Rows marked +7th need a 7th character: pick one to build the full code; its code card has its own flags.

Instructions

At T42

Excludes2

  • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.--F19.-) F10 F19

Notes that also apply

Block T36-T50 instructions (Notes 1, Includes 4, Excludes1 1, Excludes2 5, Code first 7, Use additional code 4): printed on the block page.

Chapter 19 instructions (Notes 2, Excludes2 2, Use additional code 1): printed on the chapter 19 page.

7th characters

7th characters for T42 defined here

The appropriate 7th character is to be added to each code from category T42

7th characters for T42
7thMeaning (NCHS)
Ainitial encounter
Dsubsequent encounter
Ssequela

A code that takes a 7th character is invalid without it; the placeholder X fills a code shorter than 6 characters (Official Guidelines I.A.5). How 7th characters work.

Hierarchy