Hydroxychloroquine-induced dark butterfly rash in a rheumatoid arthritis patient

Hydroxychloroquine in systemic lupus erythematosus: overview of current knowledge

The antimalarial hydroxychloroquine (HCQ) has demonstrated several crucial properties for the treatment of systemic lupus erythematosus (SLE). Herein, we reviewed the main HCQ pharmacologic features, detailed its mechanism of action, and summarized the existing guidelines and recommendations for HCQ use in rheumatology with a systematic literature search for the randomized controlled trials focused on lupus. HCQ has been shown to decrease SLE activity, especially in mild and moderate disease, to prevent disease flare and to lower the long-term glucocorticoid need. The numerous benefits of HCQ are extended to pregnancy and breastfeeding period. Based on cohort studies, antithrombotic and metabolic HCQ’s effects were shown, including lipid-lowering properties, which might contribute to an improved cardiovascular risk. Moreover, early HCQ use in antinuclear antibodies positive individuals might delay the progression to SLE. Finally, HCQ has a significant favorable impact on long-term outcomes such as damage accrual and mortality in SLE. Based on these multiple benefits, HCQ is now the mainstay long-term treatment in SLE, recommended by current guidelines in all patients unless contraindications or side effects. The daily dose associated with the best compromise between efficacy and safety is matter of debate. The concern regarding retinal toxicity rather than proper efficacy data is the one that dictated the daily dosage of ⩽5 mg/kg/day actual body weight currently agreed upon.

Hydroxychloroquine safety: A meta-analysis of randomized controlled trials

Background

Hydroxychloroquine (HCQ) is currently being examined for COVID-19. No previous meta-analysis has evaluated its side effects versus placebo. We conducted this meta-analysis to compare the safety of HCQ versus placebo.

Methods

Two authors independently searched PubMed and EMBASE databases for randomized controlled trials (RCTs) of adults comparing the adverse events (AEs) of HCQ versus placebo for any indication. Peto odds ratios (Peto ORs) and 95% confidence intervals (CIs) were calculated based on random-effects models. The heterogeneity (I²) was assessed using Cochran's Q test.

Results

Nine RCTs (eight were double-blind) with a total of 916 patients were included. HCQ caused significantly more skin pigmentation than placebo (Peto OR, 4.64; 95% CI, 1.13 to 19.00; P-value = 0.033; I² = 0%). The increase in other AEs did not reach statistical significance: rash (Peto OR, 1.11; 95% CI, 0.3 to 3.77; P-value = 0.03; I² = 0%); gastrointestinal AEs (Peto OR, 1.43; 95% CI, 0.55 to 3.72; P-value = 0.46; I² = 15.17%); headache (Peto OR, 1.94; 95% CI, 0.65 to 5.78; P-value = 0.23; I² = 9.99%); dizziness (Peto OR, 1.32; 95% CI, 0.49 to 3.52; P-value = 0.58; I² = 0%); fatigue (Peto OR, 2.13; 95% CI, 0.76 to 5.98; P-value = 0.15; I² = 0%); and visual AEs (Peto OR, 1.61; 95% CI, 0.76 to 3.41; P-value = 0.22; I² = 0%). Cardiac toxicity was not reported.

Conclusions

This meta-analysis of RCTs found a significantly higher risk of skin pigmentation in HCQ users versus placebo. More data are needed to evaluate HCQ in the context of COVID-19 treatment.