Abstract and Introduction
Purpose of Review: This review summarizes the recent literature exploring hydroxychloroquine levels and their relationship with disease activity and risk of toxicity.
Recent Findings: There is no clear correlation between weight-based dosing of hydroxychloroquine and the resulting blood levels of the medication. Recent studies have shown that increased hydroxychloroquine levels are associated with lower lupus disease activity and likely also increased risk of medication toxicity.
Summary: Mounting evidence supports use of hydroxychloroquine levels in clinical practice to document adherence and ensure safety.
Studies correlating hydroxychloroquine levels with control of lupus activity suggest that the association of higher levels with a favorable outcome may be both causal – resulting from benefit of achieving high levels – and that lower levels may indicate noncompliance. Conversely, studies of the association of levels with toxicity take into account levels achieved regardless of compliance. Articles from Petri et al. suggest there is no clear correlation between prescribed weight-based dosing of hydroxychloroquine and the resulting blood level in an individual (Figure 1) emphasizing the potential utility of following blood levels of hydroxychloroquine (HCQ) rather than relying on administrating a calculated dose. This review summarizes new literature published since an earlier review published in this journal in 2018. The data available to date support the use of hydroxychloroquine levels in clinical practice both to help achieve therapeutic levels and reduce risk of toxicity.
There is no strong correlation between a weight-based dose of hydroxychloroquine and the resultant hydroxychloroquine blood level. Reproduced with permission from Petri et al. .
Curr Opin Rheumatol. 2022;34(3):151-157. © 2022 Lippincott Williams & Wilkins