ICD-10-CM 2027
ICD-10 code for Azathioprine long-term drug therapy
Long term (current) use of inhibitors of nucleotide synthesis
From the official ICD-10-CM alphabetic index entry “Long-term (current) (prophylactic) drug therapy (use of) › azathioprine”. Page updated September 29, 2026.
About coding Azathioprine long-term drug therapy
The ICD-10-CM code for Azathioprine long-term drug therapy is Z79.624 (Long term (current) use of inhibitors of nucleotide synthesis).
Within Z79.62 (long term (current) use of immunosuppressant), Z79.624 is specifically for long term (current) use of inhibitors of nucleotide synthesis. Related codes cover immunosuppressive biologic (Z79.620), calcineurin inhibitor (Z79.621), Janus kinase inhibitor (Z79.622) and mammalian target of rapamycin (mTOR) inhibitor (Z79.623).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 949 (Aftercare with CC/MCC, relative weight 1.123) and DRG 950 (Aftercare without CC/MCC, relative weight 0.7664), in MDC 23 (Factors Influencing Health Status and Other Contacts with Health Services), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Azathioprine long-term drug therapy ICD-10 codes
What is the ICD-10 code for Azathioprine long-term drug therapy?
- Z79.624 — Long term (current) use of inhibitors of nucleotide synthesis.
Is Z79.624 billable?
- Yes. Z79.624 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Z79.624 be used as a principal diagnosis?
- No. It is not acceptable as the principal diagnosis for an inpatient stay; it may be reported as a secondary diagnosis.
Is Z79.624 a CC or MCC?
- No. Z79.624 is neither a CC nor an MCC under MS-DRG v44.0.