The drug giving rise to the adverse effect should be identified by use of codes from categories T36-T50 with fifth or sixth character 5.

Use additional code(s) to specify:
manifestations of poisoning
underdosing or failure in dosage during medical and surgical care (Y63.6, Y63.8-Y63.9)
underdosing of medication regimen (Z91.12-, Z91.13-)

Code first  , for adverse effects, the nature of the adverse effect, such as:
  adverse effect NOS (T88.7)
  aspirin gastritis (K29.-)
  blood disorders (D56-D76)
  contact dermatitis (L23-L25)
  dermatitis due to substances taken internally (L27.-)
  nephropathy (N14.0-N14.2)

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

Excludes1

  • toxic reaction to local anesthesia in pregnancy (O29.3-)

Excludes2

  • abuse and dependence of psychoactive substances (F10-F19)
  • abuse of non-dependence-producing substances (F55.-)
  • immunodeficiency due to drugs (D84.821)
  • drug reaction and poisoning affecting newborn (P00-P96)
  • pathological drug intoxication (inebriation) (F10-F19)
  1. T42 Poisoning by, adverse effect of and underdosing of antiepileptic, sedative- hypnotic and antiparkinsonism drugs

    Excludes2

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

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

    • A - initial encounter
    • D - subsequent encounter
    • S - sequela
    1. T42.0 Poisoning by, adverse effect of and underdosing of hydantoin derivatives

      1. T42.0X Poisoning by, adverse effect of and underdosing of hydantoin derivatives

        • T42.0X1 Poisoning by hydantoin derivatives, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by hydantoin derivatives NOS
        • T42.0X2 Poisoning by hydantoin derivatives, intentional self-harm
        • T42.0X3 Poisoning by hydantoin derivatives, assault
        • T42.0X4 Poisoning by hydantoin derivatives, undetermined
        • T42.0X5 Adverse effect of hydantoin derivatives
        • T42.0X6 Underdosing of hydantoin derivatives
    2. T42.1 Poisoning by, adverse effect of and underdosing of iminostilbenes

      Inclusion term(s):

      • Poisoning by, adverse effect of and underdosing of carbamazepine
      1. T42.1X Poisoning by, adverse effect of and underdosing of iminostilbenes

        • T42.1X1 Poisoning by iminostilbenes, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by iminostilbenes NOS
        • T42.1X2 Poisoning by iminostilbenes, intentional self-harm
        • T42.1X3 Poisoning by iminostilbenes, assault
        • T42.1X4 Poisoning by iminostilbenes, undetermined
        • T42.1X5 Adverse effect of iminostilbenes
        • T42.1X6 Underdosing of iminostilbenes
    3. T42.2 Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones

      1. T42.2X Poisoning by, adverse effect of and underdosing of succinimides and oxazolidinediones

        • T42.2X1 Poisoning by succinimides and oxazolidinediones, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by succinimides and oxazolidinediones NOS
        • T42.2X2 Poisoning by succinimides and oxazolidinediones, intentional self-harm
        • T42.2X3 Poisoning by succinimides and oxazolidinediones, assault
        • T42.2X4 Poisoning by succinimides and oxazolidinediones, undetermined
        • T42.2X5 Adverse effect of succinimides and oxazolidinediones
        • T42.2X6 Underdosing of succinimides and oxazolidinediones
    4. T42.3 Poisoning by, adverse effect of and underdosing of barbiturates

      1. T42.3X Poisoning by, adverse effect of and underdosing of barbiturates

        • T42.3X1 Poisoning by barbiturates, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by barbiturates NOS
        • T42.3X2 Poisoning by barbiturates, intentional self-harm
        • T42.3X3 Poisoning by barbiturates, assault
        • T42.3X4 Poisoning by barbiturates, undetermined
        • T42.3X5 Adverse effect of barbiturates
        • T42.3X6 Underdosing of barbiturates
    5. T42.4 Poisoning by, adverse effect of and underdosing of benzodiazepines

      1. T42.4X Poisoning by, adverse effect of and underdosing of benzodiazepines

        • T42.4X1 Poisoning by benzodiazepines, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by benzodiazepines NOS
        • T42.4X2 Poisoning by benzodiazepines, intentional self-harm
        • T42.4X3 Poisoning by benzodiazepines, assault
        • T42.4X4 Poisoning by benzodiazepines, undetermined
        • T42.4X5 Adverse effect of benzodiazepines
        • T42.4X6 Underdosing of benzodiazepines
    6. T42.5 Poisoning by, adverse effect of and underdosing of mixed antiepileptics

      1. T42.5X Poisoning by, adverse effect of and underdosing of antiepileptics

        • T42.5X1 Poisoning by mixed antiepileptics, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by mixed antiepileptics NOS
        • T42.5X2 Poisoning by mixed antiepileptics, intentional self-harm
        • T42.5X3 Poisoning by mixed antiepileptics, assault
        • T42.5X4 Poisoning by mixed antiepileptics, undetermined
        • T42.5X5 Adverse effect of mixed antiepileptics
        • T42.5X6 Underdosing of mixed antiepileptics
    7. T42.6 Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs

      Inclusion term(s):

      • Poisoning by, adverse effect of and underdosing of methaqualone
      • Poisoning by, adverse effect of and underdosing of valproic acid
      1. T42.6X Poisoning by, adverse effect of and underdosing of other antiepileptic and sedative-hypnotic drugs

        • T42.6X1 Poisoning by other antiepileptic and sedative-hypnotic drugs, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by other antiepileptic and sedative-hypnotic drugs NOS
        • T42.6X2 Poisoning by other antiepileptic and sedative-hypnotic drugs, intentional self-harm
        • T42.6X3 Poisoning by other antiepileptic and sedative-hypnotic drugs, assault
        • T42.6X4 Poisoning by other antiepileptic and sedative-hypnotic drugs, undetermined
        • T42.6X5 Adverse effect of other antiepileptic and sedative-hypnotic drugs
        • T42.6X6 Underdosing of other antiepileptic and sedative-hypnotic drugs
    8. T42.7 Poisoning by, adverse effect of and underdosing of unspecified antiepileptic and sedative-hypnotic drugs

      1. T42.71 Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, accidental (unintentional)

        Inclusion term(s):

        • Poisoning by antiepileptic and sedative-hypnotic drugs NOS
      2. T42.72 Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, intentional self-harm

      3. T42.73 Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, assault

      4. T42.74 Poisoning by unspecified antiepileptic and sedative-hypnotic drugs, undetermined

      5. T42.75 Adverse effect of unspecified antiepileptic and sedative-hypnotic drugs

      6. T42.76 Underdosing of unspecified antiepileptic and sedative-hypnotic drugs

    9. T42.8 Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants

      Inclusion term(s):

      • Poisoning by, adverse effect of and underdosing of amantadine
      1. T42.8X Poisoning by, adverse effect of and underdosing of antiparkinsonism drugs and other central muscle-tone depressants

        • T42.8X1 Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, accidental (unintentional)

          Inclusion term(s):

          • Poisoning by antiparkinsonism drugs and other central muscle-tone depressants NOS
        • T42.8X2 Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, intentional self-harm
        • T42.8X3 Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, assault
        • T42.8X4 Poisoning by antiparkinsonism drugs and other central muscle-tone depressants, undetermined
        • T42.8X5 Adverse effect of antiparkinsonism drugs and other central muscle-tone depressants
        • T42.8X6 Underdosing of antiparkinsonism drugs and other central muscle-tone depressants
Abbreviations used here:

NEC Not elsewhere classifiable
This abbreviation in the Tabular List represents “other specified”. When a specific code is not available for a condition, the Tabular List includes an NEC entry under a code to identify the code as the “other specified” code.

NOS Not otherwise specified
This abbreviation is the equivalent of unspecified.