Lupus & antiphospholipid syndrome
Defining Optimally Safe and Effective Blood Levels of Hydroxychloroquine in Lupus: An Important Step Toward Precision Drug Monitoring
Main finding · HCQ-related toxicityResult — go to the resultOdds of toxicity (fold higher) 2.1Authors' conclusion
The therapeutic reference range for HCQ blood level monitoring is 750 to <1,150 ng/mL.
Study context
- Population
- Patients with systemic lupus erythematosus (SLE) across SLICC, Wisconsin, international and French studies who underwent hydroxychloroquine (HCQ) blood level measurements1,842 analysed
- Participants
- 2,010 patients
- Exposure
- HCQ blood levels ≥1,150 ng/mL vs lower levels
- Outcome
- HCQ-related toxicity by HCQ blood level (upper threshold for a reference range)
Methodological detailsobservational, multicohort (SLICC, Wisconsin, international and French studies), adjusted spline and logistic regression
- Observational
- Multicohort (SLICC, Wisconsin, international and French studies)
- Adjusted spline and logistic regression
Main finding
HCQ-related toxicity
Odds of toxicity (fold higher)
2.1
As reported in the abstract
- Patients with HCQ-related toxicity
- 4.9%
Observational data: associations, not effects.
Further findings
HCQ-related toxicity per 1,000-g increase in cumulative HCQ dose
- Odds of toxicity fold higher per 1,000-g cumulative dose increase
- 1.7
Therapeutic effect (SLEDAI-2K ≥6)
- Blood levels ≥1,150 ng/mL associated with a saturation in therapeutic effect (supratherapeutic)
Supratherapeutic HCQ levels (≥1,150 ng/mL) by chronic kidney disease (CKD) stage
- Odds fold higher with CKD stage ≥3
- 2.3
Original publication
Defining Optimally Safe and Effective Blood Levels of Hydroxychloroquine in Lupus: An Important Step Toward Precision Drug Monitoring. Arthritis Rheumatol. Published 17 February 2026. doi:10.
Composed by AI from the published abstract and checked against it. How Briefs are made →