Optimal patient dosing for is ≤5.0 mg/kg of actual (real) body weight or 400 mg daily, whichever is lower, for most patients.
Whole blood HCQ levels should be checked in patients not adequately responding, with goals for efficacy being >750 ng/ml and for compliance being >500 ng/ml.
Smokers should be educated about benefits of cessation, but effects of smoking on HCQ therapy are unclear and HCQ treatment should still be attempted in lieu of other, more potent immunosuppressive medications.
Expert opinion suggests HCQ can be continued during both pregnancy and lactation in patients felt to be benefiting from it.
The biggest risk factor for HCQ ocular toxicity is daily dose, with safe dosing believed to be 4-5 mg/kg.
Caution should be exercised when considering HCQ use in patients with pre-existing maculopathy or renal disease (50% reduction in renal function correlates with 2x retinopathy risk), long-term HCQ users, and women concurrently taking tamoxifen (increases retinopathy risk about fivefold). Hepatic disease and older age were thought to be retinopathy risk factors, but this was recently disputed.
Baseline screening for HCQ-induced ocular toxicity should be performed within the 1st year of treatment (implying HCQ can be started prior to baseline screening).
Annual ocular toxicity screening is recommended to begin only after 5 years of use unless patients are considered high-risk or develop ophthalmologic symptoms.
Amsler grids are no longer appropriate for screening.
Appropriate ocular toxicity testing should include 10–2 visual field testing and spectral domain ocular coherence tomography.
Bruising may be a risk factor for the development of HCQ-induced hyperpigmentation.