T40.99 — Poisoning by, adverse effect of and underdosing of other psychodysleptics [hallucinogens]

Not billable

Is T40.99 billable?

No — T40.99 is a non-billable header code. T40.99 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 18 billable codes beneath T40.99.

Billable codes under this header

T40.99 at a glance

Code	T40.99
Description	Poisoning by, adverse effect of and underdosing of other psychodysleptics [hallucinogens]
Billable	No — header code
Code set	ICD-10-CM FY2027
Valid for encounters	October 1, 2026 – September 30, 2027

Excludes1 — never code together — inherited from T36-T50

The conditions below can never be reported together with T40.99 on the same claim. An Excludes1 note means the two conditions cannot occur in the same patient, so reporting both is a coding error.

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

Code first — inherited from T36-T50

The underlying condition below must be sequenced before T40.99. T40.99 describes a manifestation and cannot be the principal or first-listed diagnosis.

, 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)

Use additional code — inherited from Chapter 19

Report an additional code alongside T40.99 to fully describe the condition. T40.99 is sequenced first.

code to identify any retained foreign body, if applicable (Z18.-)

Use additional code — inherited from T36-T50

Report an additional code alongside T40.99 to fully describe the condition. T40.99 is sequenced first.

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-)

Excludes2 — not included here — inherited from Chapter 19

The conditions below are not part of T40.99, but a patient may have both at the same time. When documentation supports it, T40.99 and the excluded code may both be reported.

birth trauma (P10-P15)
obstetric trauma (O70-O71)

Excludes2 — not included here — inherited from T36-T50

The conditions below are not part of T40.99, but a patient may have both at the same time. When documentation supports it, T40.99 and the excluded code may both be reported.

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)

Excludes2 — not included here — inherited from T40

The conditions below are not part of T40.99, but a patient may have both at the same time. When documentation supports it, T40.99 and the excluded code may both be reported.

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

What codes fall under T40.99? (6)

How long has T40.99 existed?

T40.99 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.

Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.

What other codes are in the T40.9 family? (1)

T40.90Poisoning by, adverse effect of and underdosing of unspecified psychodysleptics [hallucinogens]not billable