2027 ICD-10-CM Diagnosis Code T50.995AAdverse effect of other drugs, medicaments and biological substances, initial encounter
T50.995A is a billable ICD-10-CM diagnosis code for adverse effect of other drugs, medicaments and biological substances, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 791, 793, 917 through 918. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Adverse effects of drugs and medicaments, initial encounter.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Acitretin adverse reaction
- Adverse cutaneous reaction to herbal medicine
- Adverse cutaneous reaction to homeopathic medicine
- Adverse reaction caused by bisphosphonate
- Adverse reaction caused by canagliflozin
- Adverse reaction caused by dapagliflozin
- Adverse reaction caused by empagliflozin
- Adverse reaction caused by ertugliflozin
- Adverse reaction to allergenic extract
- Adverse reaction to aluminum and/or aluminum compound
- Adverse reaction to bile acid and/or bile acid derivative
- Adverse reaction to bone resorption inhibitor
- Adverse reaction to calcium carbonate and/or etidronic acid
- Adverse reaction to chenodeoxycholic acid and/or ursodeoxycholic acid
- Adverse reaction to clodronic acid
- Adverse reaction to drug primarily acting on nutrition
- Adverse reaction to etidronic acid
- Adverse reaction to fatty acid
- Adverse reaction to Fuller's earth
- Adverse reaction to glycol
- Adverse reaction to hyaluronic acid
- Adverse reaction to inorganic chemical
- Adverse reaction to oil
- Adverse reaction to pamidronic acid
- Adverse reaction to parathyroid hormone and/or parathyroid hormone derivative
- Adverse reaction to phosphodiesterase 5 inhibitor
- Adverse reaction to substance with sodium glucose cotransporter subtype 2 inhibitor mechanism of action
- Aldehyde dehydrogenase inhibitor adverse reaction
- Anionic surfactant adverse reaction
- Antidotes for pesticides adverse reaction
- Bone pain caused by granulocyte colony stimulating factor
- Bufexamac adverse reaction
- Calcitonin adverse reaction
- Calcium polystyrene sulfonate adverse reaction
- Calcium regulating agent adverse reaction
- Calcium regulating hormone adverse reaction
- Carbomer-940 adverse reaction
- Cation exchange resin adverse reaction
- Cellulose-derived viscosity modifier adverse reaction
- Chorea caused by dopamine receptor antagonist
- Citrate adverse reaction
- Colchicum alkaloid adverse reaction
- Collagen adverse reaction
- Colony stimulating factors adverse reaction
- Dimethyl-ether propane adverse reaction
- Drug reaction with eosinophilia and systemic symptoms
- Drug reaction with eosinophilia and systemic symptoms caused by strontium ranelate
- Drug-induced dystonia
- Drug-induced uveitis
- Dystonia caused by dopamine receptor antagonist
- Ear wax removal preparation adverse reaction
- Electrolyte anion adverse reaction
- Enbucrilate adverse reaction
- Ergoline drug adverse reaction
- Etretinate adverse reaction
- Filgrastim adverse reaction
- Fixed oil adverse reaction
- Fluoride adverse reaction
- Gold nephropathy
- Hemostatic adverse reaction
- Herbal medicine adverse reaction
- Homeopathic medicine adverse reaction
- Immunostimulant adverse reaction
- Inositol adverse reaction
- Ion exchange resin adverse reaction
- Isotretinoin adverse reaction
- Lenograstim adverse reaction
- Methyl methacrylate embolism
- Molgramostim adverse reaction
- Nicotine adverse reaction
- Non-ionic surfactant adverse reaction
- Oral leukoplakia caused by sanguinarine
- Osteonecrosis of jaw
- Osteonecrosis of jaw caused by bisphosphonate
- Osteonecrosis of jaw caused by drug
- Pamidronic acid-induced uveitis
- Parkinsonism caused by dopamine depleting agent
- Parkinsonism caused by dopamine receptor antagonist
- Parkinsonism caused by drug
- p-di-Isobutylphenoxypolyethoxyethanol adverse reaction
- Phosphodiesterase inhibitor adverse reaction
- Radiopharmaceutical adverse reaction
- Retinoid adverse reaction
- Retinopathy caused by canthaxanthin
- Salmon calcitonin adverse reaction
- Sodium fluoride adverse reaction
- Surgical tissue adhesive adverse reaction
- Terpenes adverse reaction
- Toxic chorea
- Toxic dystonia
- Urinary disorder monitoring status
- Urinary drug side effect
- Ursodeoxycholic acid adverse reaction
- Viscosity modifier adverse reaction
- Xanthine oxidase inhibitor adverse reaction
Coding GuidelinesGuidance
When coding an adverse effect of a drug that has been correctly prescribed and properly administered, assign the appropriate code for the nature of the adverse effect followed by the appropriate code for the adverse effect of the drug.
The appropriate 7th character is to be added to each code from block Poisoning by, adverse effect of and underdosing of diuretics and other and unspecified drugs, medicaments and biological substances (T50). Use the following options for the applicable episode of care:
- A - initial encounter
- D - subsequent encounter
- S - sequela
Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to T50.995A: its own notes plus those printed at T50, block T36-T50, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.
Includes
Further defines, or gives examples of, the content of the category.
- 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
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- toxic reaction to local anesthesia in pregnancy (O29.3-)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Code First
The underlying condition named in the note is sequenced before this code.
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify any retained foreign body, if applicable (Z18.-)
Notes
General instructions on how these codes are used.
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
7th Character
Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.
- The appropriate 7th character is to be added to each code from category T50
- Ainitial encounter this code
- Dsubsequent encounter
- Ssequela
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name T50.995A, its category, or a range that includes it.
Excludes1 1
These codes carry an Excludes1 note naming T50.995A: they are not reported together with it, unless the two conditions are unrelated.
Use Additional Code 1
These codes say to use an additional code from the note, and T50.995A is one of the codes named.
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Table of Drugs and ChemicalsClinical
Substances in the Table of Drugs and Chemicals that reference this code family. Always confirm in the Tabular List before coding.
Patient EducationClinical
Drug Reactions
Most of the time, medicines make our lives better. They reduce aches and pains, fight infections, and control problems such as high blood pressure or diabetes. But medicines can also cause unwanted reactions, such as drug interactions, side effects, and allergies.
The full article covers:
- What is a drug interaction?
- What are side effects?
- What are drug allergies?
- How can I stay safe when taking medicines?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert T50.995A to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About T50.995AOverview
Is T50.995A a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report adverse effect of other drugs, medicaments and biological substances, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What does the 7th character A in T50.995A mean?
The final character A marks the initial encounter: use it while the patient is receiving active treatment for adverse effect of other drugs, medicaments and biological substances, such as an emergency visit or first evaluation.
What MS-DRG does T50.995A group to?
When adverse effect of other drugs, medicaments and biological substances, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 918, 917, with relative weights from 0.8716 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Can T50.995A be reported with a code from O29.3?
Not as a rule. The Excludes1 note at block T36-T50, which applies to T50.995A, lists "toxic reaction to local anesthesia in pregnancy (O29.3-)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).
What is the ICD-9 equivalent of T50.995A?
Under the General Equivalence Mappings, adverse effect of other drugs, medicaments and biological substances, initial encounter converts to ICD-9-CM 995.29 (adv eff med/biol NEC/NOS) and E947.8 (adv eff medicinal NEC). The mapping is approximate, so confirm the match fits the documentation.
