T43.016A
✓ BillableUnderdosing of tricyclic antidepressants, initial encounter
Injury, poisoning and certain other consequences of external causes (S00-T88)
⚠️ Excludes2
inheritedRules inherited from parent codes.
- • appetite depressants (T50.5-)
- • barbiturates (T42.3-)
- • benzodiazepines (T42.4-)
- • drug dependence and related mental and behavioral disorders due to psychoactive substance use (F10.- -F19.-)
- • methaqualone (T42.6-)
- • psychodysleptics [hallucinogens] (T40.7-T40.9-)
Clinical Description
ICD-10-CM code T43.016A represents underdosing of tricyclic antidepressants, initial encounter. This code falls under the Injury, poisoning and certain other consequences of external causes (S00-T88) classification. It is a billable/specific code valid for HIPAA-covered transactions as of October 1, 2025 (FY2026). This code can be used to indicate a diagnosis for reimbursement purposes on insurance claims.
This is a 8-character code at the 7th level of specificity. This is the most specific code available in this subcategory.
Frequently Asked Questions
What is ICD-10 code T43.016A?
ICD-10-CM code T43.016A is "Underdosing of tricyclic antidepressants, initial encounter". It belongs to the category: Injury, poisoning and certain other consequences of external causes (S00-T88).
Is T43.016A a billable ICD-10 code?
Yes, T43.016A is a billable/specific ICD-10-CM code that can be used to indicate a diagnosis for reimbursement purposes.
Can T43.016A be coded with other codes?
T43.016A has 6 Excludes2 note(s). These conditions can be coded together if both are documented in the patient record.
Related Codes in T43.016
Other codes in the same category that may be relevant for differential coding:
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Data Source
CMS ICD-10-CM 2026 Tabular List
Updated October 1, 2025 (FY2026)