In #SLE, #HCQ levels >1150 ng/ml ↑toxicity risk w/o added benefit. Levels 750-1150 ng/ml linked to ↓disease activity. CKD stage ≥3 doubled HCQ levels at same dose. Supports monitoring & dose adjustment in CKD to balance safety & efficacy. @RheumNow #EULAR2025 #OP0199