Perspective Chapter: Effect of Azathioprine and Hydroxychloroquine in Reducing Steroids in Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) requires long-term disease suppression while avoiding the cumulative toxicity of corticosteroids. Hydroxychloroquine (HCQ) is the universal therapeutic foundation for SLE, supported by robust evidence linking its continuous use to fewer disease flares, improved survival, and reduced glucocorticoid dependence. Azathioprine (AZA) is a well-established immunosuppressive alternative that is compatible with pregnancy and useful in both mild-to-moderate systemic disease and post-induction maintenance, including lupus nephritis. Observational data and major guideline recommendations underscore the complementary steroid-sparing benefits of HCQ and AZA, either individually or in combination, particularly when minimizing glucocorticoid exposure is a clinical priority or when mycophenolate mofetil is contraindicated. This chapter reviews the pharmacological properties, organ-specific indications, and safety profiles of these agents and outlines practical strategies for tapering glucocorticoids. Comprehensive summaries of AZA-related adverse effects and clinically relevant drug interactions are also provided to assist in therapeutic decision-making in routine rheumatology practice.