For non-malignant conditions, consider alternative non-thiopurine immunosuppressant therapy. For malignancy, start with drastically reduced doses (reduce daily dose by 10-fold and dose thrice weekly instead of daily) and adjust doses of azathioprine based on degree of myelosuppression and disease-specific guidelines. Allow 4-6 weeks to reach steady-state after each dose adjustment (PMID 16530578, 11302950, 15606506, 16530532, 12477776).