ICD-10-CM guide
Z79 Codes for Long-Term Drug Therapy: When and How to Use Them
When to add a Z79 long-term (current) drug therapy code, which drugs it covers, when it is not used, and how it pairs with the condition code.
Reviewed 2026-09-29 | 2 min read
Category Z79 answers a question the diagnosis code cannot: is the patient on ongoing medication for this condition? A long-term inhaled steroid, a bisphosphonate, insulin, or daily aspirin can all affect how a patient is managed. These codes are easy to forget because the condition code already looks complete, and easy to overuse because not every prescription is long-term therapy.
What Z79 describes
A Z79 code indicates a patient's continuous use of a prescribed drug, including drugs such as aspirin therapy, for the long-term treatment of a condition or for prophylactic use. It is a status code: it adds information that may affect the course of treatment, and it is reported in addition to the code for the condition.
Common Z79 codes in outpatient charts
- Z79.4, Long term (current) use of insulin.
- Z79.84, Long term (current) use of oral hypoglycemic drugs.
- Z79.85, Long-term (current) use of injectable non-insulin antidiabetic drugs.
- Z79.51, Long term (current) use of inhaled steroids.
- Z79.83, Long term (current) use of bisphosphonates.
Pair it with the condition, not in place of it
The condition code comes from the body system chapter and carries the diagnosis. The Z79 code follows it. Mild persistent asthma managed on a daily inhaled steroid is J45.30 with Z79.51. Osteoporosis without a current fracture on a bisphosphonate is M81.0 with Z79.83. Type 2 diabetes on insulin with hyperglycemia is E11.65 with Z79.4.
A status code should not be added when the diagnosis code already includes the information the status code provides. Check the diagnosis code title before adding one.
When not to use Z79
- Not for patients with a drug addiction. Code the drug use, abuse, or dependence instead.
- Not for medications used for detoxification or maintenance programs to prevent withdrawal, such as methadone maintenance. Code the dependence instead.
- Not for a one-time or temporary dose. Insulin given temporarily to control a type 2 patient's blood sugar during an encounter is not Z79.4.
- Not for therapeutic drug level monitoring, which the Tabular List classifies to Z51.81.
Status is not history
A status code describes something that is still true, such as current medication use. A history code describes a condition the patient no longer has. Z79 applies only while the patient is still on the therapy. A medication the patient stopped taking is not current long-term use.
Questions coders ask
- How long does a drug need to be taken to use Z79?
- The guideline does not set a duration. Z79 describes continuous use of a prescribed drug for long-term treatment or prophylaxis, as documented in the record, rather than a temporary or one-time dose.
- Can I report more than one Z79 code?
- Yes. Report a Z79 code for each relevant long-term drug class. For example, a patient on both insulin and an oral hypoglycemic drug gets Z79.4 and Z79.84.
- Is Z79 ever the first-listed code?
- In a typical outpatient visit for a condition, no. The condition that was chiefly responsible for the visit is first, and the Z79 code adds treatment status after it.
Practice these rules
Sources
ICD-10-CM Official Guidelines for Coding and Reporting FY 2027
Section I.C.21.c.3, Status, category Z79
ICD-10-CM Official Guidelines for Coding and Reporting FY 2027
Section I.C.4.a.3, Diabetes mellitus and the use of insulin, oral hypoglycemics, and injectable non-insulin drugs
ICD-10-CM Official Guidelines for Coding and Reporting FY 2027
Section IV.G, ICD-10-CM code for the reason for encounter/visit
FY 2027 ICD-10-CM Tabular List and Alphabetic Index
Tabular List, category Z79
FY 2027 ICD-10-CM Code Descriptions in Tabular Order
Codes Z79.4, Z79.51, Z79.83, Z79.84, Z79.85, J45.30, M81.0, E11.65