Although low [HCQ] is associated with higher SLE activity, adapting the HCQ dose did not reduce SLE flares over a 7-month follow-up.

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Objective Blood concentrations of hydroxychloroquine (HCQ) vary widely among patients with systemic lupus erythematosus (SLE). A pharmacokinetic/pharmacodynamic relationship has been found in different situations, and a very low blood concentration of HCQ is a simple marker of nonadherence to treatment. Therefore, interest in blood HCQ concentration measurement has increased, but little is known about factors that influence blood HCQ concentration variability. This study was undertaken to analyze determinants of blood HCQ concentrations. Methods We conducted a retrospective analysis of patient data, including data from the Plaquenil Lupus Systemic (PLUS) study, to determine the association of epidemiologic, clinical, and biologic factors with blood HCQ concentrations. Data for nonadherent patients (blood HCQ concentration <200 ng/ml) were excluded. Results To examine homogeneous pharmacologic data, we restricted the analyses of the PLUS data to the 509 SLE patients receiving 400 mg/day. We found no association of ethnicity or smoking with blood HCQ concentrations and no pharmacokinetic drug–drug interaction with antacids or with inhibitors or inducers of cytochrome P450 enzymes. On multivariate analysis, high body mass index (P = 0.008), no treatment with corticosteroids (P = 0.04), increased time between the last tablet intake and measurement of blood HCQ concentrations (P = 0.017), low platelet count (P < 0.001), low neutrophil count (P < 0.001), and high estimated creatinine clearance (P < 0.001) were associated with low blood HCQ concentrations. In 22 SLE patients with chronic renal insufficiency (median serum creatinine clearance 52 ml/minute [range 23–58 ml/minute]) who received 400 mg/day HCQ, the median blood HCQ concentration was significantly higher than that in the 509 patients from the PLUS study (1,338 ng/ml [range 504–2,229 ng/ml] versus 917 ng/ml [range 208–3316 ng/ml]) (P < 0.001). Conclusion We provide a comprehensive analysis of determinants of blood HCQ concentrations. Because this measurement is increasingly being used, these data might be useful for clinicians.

Hydroxychloroquine-induced pigmentation is not a rare adverse effect of HCQ. Our data support the hypothesis that HCQ-induced pigmentation is secondary to ecchymosis or bruising.

Hydroxychloroquine (HCQ) and chloroquine have been used for more than 50 years to treat systemic lupus erythematosus (SLE) and other rheumatic diseases. In general, these drugs are well tolerated and rarely need to be discontinued because of an adverse systemic reaction. However, both medications can be irreversibly toxic to the retina. A new study indicates that toxicity is not as rare as once believed, but depends critically on daily dosage and duration of use, as well as other risk factors. With attention to dosage and other factors, and with proper screening for early signs of toxicity, HCQ can be prescribed with relative safety even over long periods of time.

Introduction Hydroxychloroquine is an antimalarial agent widely prescribed in internal medicine, rheumatology and dermatology. Its use can be complicated by various side effects including skin pigmentation. Objectives The aim of the study is to review epidemiological, clinical features and risk factors of hydroxychloroquine-induced pigmentation. Materials and methods We performed a cross-sectional study conducted over a period of 5 months. During this period, patients who had been treated with hydroxychloroquine for over 6 months, in the internal medicine department, underwent a complete dermatological examination. All patients completed a structured questionnaire to collect demographic data, dosage and treatment duration of hydroxychloroquine, other drug intake, hydroxychloroquine indication, and presence of pigmentary changes on the skin, nail, hair, and mucosa. Results A total of 41 patients (38 women and 3 men) were included in the study. The mean age was 39.2 ± 15.4 years. The hydroxychloroquine was indicated for systemic lupus erythematosus in 73.2%, dermatomyositis in 12.2%, rheumatoid arthritis in 9.8%, actinic lichen and sarcoidosis each in 2.4%. Cutaneous pigmented lesions were found in 21 cases (51%), mucous pigmentation in 5 cases (12%) and nail pigmentation in 1 case (2.5%). In 12 of 41 (29%) of the hydroxychloroquine users, we conclude a hydroxychloroquine-induced pigmentation. There were 11 women and one man with a mean age of 43 years and all of them were systemic lupus erythematosus patients. Pigmented lesions were located on the lower limbs in seven cases, the face in two cases, lips in two cases and the gum in two cases. Pigmentation appeared after a median duration of hydroxychloroquine treatment of 32 months with a median cumulative dose of 361 g. Overall, two patients reported that the appearance of pigmented lesions was preceded by the occurrence of ecchymotic areas following microtrauma. Significant association was found between hydroxychloroquine-induced pigmentation and treatment with oral anticoagulants and/or antiplatelet agents ( p = 0.03). Conclusion Our systematic examination of patients demonstrated that hydroxychloroquine-induced pigmentation is not rare. The imputability of hydroxychloroquine in the genesis of this discoloration is difficult to establish. Our study supports the hypothesis that ecchymosis, platelet antiaggregants and oral anticoagulants may be the main predisposing factors to hydroxychloroquine-induced pigmentation.

The coexistence of systemic lupus erythematosus (SLE) and myasthenia gravis (MG) is rarely reported, and most of the published studies are case reports. Hydroxychloroquine, an antimalarial agent, is an essential treatment in patients with SLE but special caution is recommended when used in MG patients. We retrospectively analyzed the clinical features, laboratory findings, and outcome of 17 patients with both diseases with a special focus regarding hydroxychloroquine use and with a review of the literature. All patients were women. The mean age at MG onset and SLE diagnosis was 34.5 [14-64] and 37.8 [18-72] years, respectively. The presenting symptoms of MG were limb weakness (94%), ocular (88%) and bulbar involvement (53%). Autoantibodies against the acetylcholine receptor were positive in 94% of cases. The main manifestations of SLE included arthritis (88%), cytopenias (53%) and skin rash (41%). Treatment of SLE required hydroxychloroquine (94%), steroids (47%) and immunosuppressive drugs (18%). Among eight patients (47%) who developed MG after initiation of hydroxychloroquine, the question of induction of MG by hydroxychloroquine was raised in one patient. On the other hand, an exacerbation of myasthenic symptoms was only seen in one of the eight patients who received hydroxychloroquine after the diagnosis of MG. Including our cases, we reviewed a total of 70 patients with SLE and MG. Compared with a large series of 1,000 unselected SLE patients, those with associated MG were older, had lower incidence of cutaneous, renal, and neurological manifestations, and higher frequency of anticardiolipin antibodies and lupus anticoagulant. In conclusion, the clinical pattern of patients with SLE and MG seems to be characterized by a less severe course of SLE and higher frequency of antiphospholipid antibodies. Hydroxychloroquine treatment appears to be safe in this setting.

We conducted this study to characterize the relationship between primary Sjögren syndrome (pSS)-associated peripheral neuropathy (PN) and markers of B-cell monoclonal proliferation and chronic activation. The cohort included 120 consecutive patients presenting with definite pSS according to the American-European Consensus Group criteria. Serum markers of chronic B-cell activation included autoantibodies and hypergammaglobulinemia. Markers of monoclonal B-cell proliferation included mixed cryoglobulin, monoclonal gammopathy, abnormal κ/λ free light chain (FLC) ratio, and B-cell non-Hodgkin lymphoma (B-NHL). Definite PN was present in 30 patients (25%) including 7 patients (23%) with sensorimotor neuropathy, 3 patients (10%) with ataxic sensory neuropathy, and 20 patients (67%) with nonataxic sensory neuropathy. Patients with a sensorimotor neuropathy differed from those without PN by higher rates of monoclonal B-cell proliferation markers, that is, mixed cryoglobulin (57% vs. 11%; p = 0.008), monoclonal gammopathy (71% vs. 17%; p = 0.004), higher FLC ratio (2.7 ± 1.5 vs. 1.7 ± 1.8; p = 0.024), and B-NHL (57% vs. 3%; p < 0.001). Patients with nonataxic sensory neuropathy were characterized by a higher age (57.5 ± 10.7 vs. 48.7 ± 14.3 years; p = 0.007), more frequent central nervous system (CNS) involvement (15% vs. 2%; p = 0.04) and a lower prevalence of chronic B-cell activation serum markers, that is, antinuclear antibodies (ANA) (60% vs. 90%; p = 0.003), anti-SSA (Ro) (40% vs. 72%; p = 0.009), anti-SSB (La) (15% vs. 41%; p = 0.039), rheumatoid factor (37% vs. 67%; p = 0.02), and hypergammaglobulinemia (35% vs. 64%; p = 0.023). In multivariate analysis, sensorimotor neuropathy was associated with the presence of B-NHL (odds ratio [OR], 39.0; p < 0.001), whereas nonataxic sensory neuropathy was associated with the presence of CNS involvement (OR, 17.0; p = 0.025) and ANA (OR, 0.07; p < 0.001). In conclusion, we found that up to 25% of pSS patients presented with PN, predominantly sensory neuropathy. Distinctive immunologic profiles were found according to the type of SS-associated neuropathy: nonataxic sensory neuropathy was marked by a low prevalence of B-cell activation markers, and sensorimotor neuropathy was marked by a high prevalence of B-cell monoclonal proliferation markers.