I agree with LisaAlonso23. I'd also just like to add a few more things I found regarding Z79. Hope this helps!
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Z79 - Long-term (current) drug therapy (pages 92-93)
Codes from this category indicate a patient’s continuous use of a prescribed drug (including such things as aspirin therapy) for the long-term treatment of a condition or for prophylactic use. It is not for use for patients who have addictions to drugs. This subcategory is not for use of medications for detoxification or maintenance programs to prevent withdrawal symptoms (e.g., methadone maintenance for opiate dependence). Assign the appropriate code for the drug use, abuse, or dependence instead.
Assign a code from Z79 if the patient is receiving a medication for an extended period as a prophylactic measure (such as for the prevention of deep vein thrombosis) or as treatment of a chronic condition (such as arthritis) or a disease requiring a lengthy course of treatment (such as cancer). Do not assign a code from category Z79 for medication being administered for a brief period of time to treat an acute illness or injury (such as a course of antibiotics to treat acute bronchitis).
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ICD-10-CM/PCS Coding Clinic, First Quarter ICD-10 2021 Pages: 12-13 Effective with discharges: March 10, 2021
Question:
A patient diagnosed with asthma is currently on prescribed inhaled albuterol, "as needed" for control of symptoms. Since the medication is prescribed for long-term treatment of asthma, would it be appropriate to assign a code from category Z79, Long-term (current) drug therapy, even though the medication is taken pro re nata (PRN) to control symptoms of asthma?
Answer:
Medications that are prescribed on an as needed (PRN) basis would not be assigned codes from category Z79, Long-term (current) drug therapy. For example, rescue medications used to relieve asthma symptoms are not classified as long-term drug therapy.
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Format and Conventions and Current Coding Practices for ICD-10-CM and ICD-10-PCS
Chapter 11 Z Codes and External Cause of Morbidity Codes
Z Codes
Codes Representing Patient History, Status, or Problems
Codes from category Z79 are assigned to indicate a patient's continuous use of a prescribed drug for an extended period. For example, codes from category Z79 are assigned for long-term use of medication:
- As a prophylactic measure (e.g., to prevent deep vein thrombosis)
- As treatment of a chronic condition (e.g., arthritis)
- For a disease requiring a lengthy course of treatment (e.g., cancer)
A code from category Z79 is appropriately assigned when the patient is currently receiving long-term anticoagulant therapy (Z79.01), antithrombotics/antiplatelets (Z79.02), nonsteroidal anti-inflammatories (Z79.1), antibiotic therapy (Z79.2), hormonal contraceptives (Z79.3), insulin (Z79.4), steroids (Z79.51-Z79.52), immunomodulators and immunosuppressants (Z79.60-Z79.69) or other long-term drug therapy (Z79.81-Z79.899). Subcategory Z79.8 includes long-term use of selective estrogen receptor modulators (Z79.810), aromatase inhibitors (Z79.811), other agents affecting estrogen receptors and estrogen levels (Z79.818), aspirin (Z79.82), bisphosphonates (Z79.83), oral hypoglycemic drugs (Z79.84), injectable non-insulin antidiabetic drugs (Z79.85), hormone replacement therapy (Z79.890), opiate analgesic (Z79.891), and other long-term drug therapy (Z79.899). An additional code is assigned for the condition for which the medication is prescribed.
Note that coding guidelines do not provide a definition or time frame for long-term drug therapy. If a patient receives a drug on a regular basis and has multiple refills available for a prescription, it is appropriate to document long-term drug use. Documentation of long-term drug use is at the discretion of the health care provider.
Do not assign a code from category Z79 when the medication is prescribed to treat an acute illness or injury and is being given for a brief period of time (e.g., antibiotics to treat bronchitis). Codes from category Z79 are also not used when medications are given for detoxification or maintenance programs used to prevent withdrawal symptoms in patients with drug dependence. For example, long-term use of methadone for pain management is coded with Z79.891, Long term (current) use of opiate analgesic, but the use of methadone in a maintenance program to prevent withdrawal symptoms is coded using the drug dependence code (F11.2-).
Code Z51.81 is used to report encounters for therapeutic drug monitoring. If the drug being monitored is one that the patient has been receiving on a long-term basis, a code from category Z79 should be added.