Z79.811 Long term (current) use of aromatase inhibitors

Billable ICD-10-CM code, FY2026. Exempt from present-on-admission (POA) reporting.

Applicable to

• Long term (current) use of anastrozole (Arimidex)
• Long term (current) use of exemestane (Aromasin)
• Long term (current) use of letrozole (Femara)

Applies from Z79 Long term (current) drug therapy

Includes

• long term (current) drug use for prophylactic purposes

Excludes2 (not included here)

• drug abuse and dependence (F11-F19)
• drug use complicating pregnancy, childbirth, and the puerperium (O99.32-)

Code also

• any therapeutic drug level monitoring (Z51.81)

Applies from Z79.81 Long term (current) use of agents affecting estrogen receptors and estrogen levels

Excludes1 (never code together)

• hormone replacement therapy (Z79.890)

Code first

• , if applicable:
• malignant neoplasm of breast (C50.-)
• malignant neoplasm of prostate (C61)

Use additional code

• code, if applicable, to identify:
• estrogen receptor positive status (Z17.0)
• family history of breast cancer (Z80.3)
• genetic susceptibility to malignant neoplasm (cancer) (Z15.0-)
• personal history of breast cancer (Z85.3)
• personal history of prostate cancer (Z85.46)
• postmenopausal status (Z78.0)

MS-DRG index

Defines the logic of DRG(s) 951 in MDC 23.

Approximate ICD-9-CM (GEMs)

• V07.52 Use of aromatase inhibitors

Medicare Code Edits (MCE v43.1 (April 2026))

• Unacceptable principal diagnosis: These codes describe a circumstance which influences care but is not a current illness or injury, or capture only an underlying condition, and are unacceptable as principal diagnosis.

Code annotations containing back-references to Z79.811

Back-references to Z79.81

• Type 2 Excludes: Z79.6 Long term (current) use of immunomodulators and immunosuppressants ("long term (current) use of agents affecting estrogen receptors and estrogen levels (Z79.81-)")

Back-references to Z79

• Code Also: Z51.81 Encounter for therapeutic drug level monitoring ("any long-term (current) drug therapy (Z79.-)")
• Type 2 Excludes: Z92.2 Personal history of drug therapy ("long term (current) drug therapy (Z79.-)")

Diagnosis Index entries for Z79.811

• Long-term (current) (prophylactic) drug therapy (use of) › anastrozole (Arimidex)
• Long-term (current) (prophylactic) drug therapy (use of) › aromatase inhibitors
• Long-term (current) (prophylactic) drug therapy (use of) › exemestane (Aromasin)
• Long-term (current) (prophylactic) drug therapy (use of) › letrozole (Femara)
• Therapy › drug, long-term (current) (prophylactic) › anastrozole (Arimidex)
• Therapy › drug, long-term (current) (prophylactic) › aromatase inhibitors
• Therapy › drug, long-term (current) (prophylactic) › exemestane (Aromasin)
• Therapy › drug, long-term (current) (prophylactic) › letrozole (Femara)

Nearby codes

• Z79.64 Long term (current) use of myelosuppressive agent
• Z79.69 Long term (current) use of other immunomodulators and immunosuppressants
• Z79.8 Other long term (current) drug therapy
• Z79.81 Long term (current) use of agents affecting estrogen receptors and estrogen levels
• Z79.810 Long term (current) use of selective estrogen receptor modulators (SERMs)
• Z79.811 Long term (current) use of aromatase inhibitors (this code)
• Z79.818 Long term (current) use of other agents affecting estrogen receptors and estrogen levels
• Z79.82 Long term (current) use of aspirin
• Z79.83 Long term (current) use of bisphosphonates
• Z79.84 Long term (current) use of oral hypoglycemic drugs
• Z79.85 Long-term (current) use of injectable non-insulin antidiabetic drugs