Arthritis Rheumatol

Optimal hydroxychloroquine levels identified in lupus patients

January 16, 2026

An observational study of 1,842 patients with systemic lupus erythematosus found that hydroxychloroquine (HCQ) blood levels ≥1,150 ng/mL were associated with a 2.1-fold higher risk of toxicity without added benefit for disease control. Therapeutic reference range was defined as 750 to <1,150 ng/mL. Chronic kidney disease (CKD) stage ≥3 increased odds of supratherapeutic levels by 2.3-fold. These findings suggest that routine HCQ blood level monitoring could optimize dosing and minimize harm, particularly in patients with impaired renal function.

Clinical takeaway: Target HCQ blood levels between 750 and <1,150 ng/mL; consider monitoring in patients with CKD to avoid toxicity.

Source:

Garg S, et al. (2025, December 9). Arthritis Rheumatol. Defining Optimally Safe and Effective Blood Levels of Hydroxychloroquine in Lupus: An Important Step toward Precision Drug Monitoring. https://pubmed.ncbi.nlm.nih.gov/41367131/