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PubMed1994

Stereoselective distribution of hydroxychloroquine in the rabbit following single and multiple oral doses of the racemate and the separate enantiomers.

Hydroxychloroquine (HCQ) stereoselective distribution was investigated in rabbits after 20 mg/kg po of racemic-HCQ (rac-HCQ) and 20 mg/kg po of each enantiomer, 97% pure (-)-(R)-HCQ and 99% pure (+)-(S)-HCQ. Concentrations were 4 to 6 times higher in whole blood than in plasma. Melanin did not affect plasma and whole blood levels since concentrations did not differ between pigmented and nonpigmented animals. After single and multiple doses of the separate enantiomers, only 5-10% of the antipode could be measured, in blood or plasma. Therefore, there was no significant interconversion from one enantiomer into the other. Following rac-HCQ, plasma (+)-(S)-levels always surpassed (-)-(R)-ones while in whole blood, (-)-(R)-HCQ concentrations were always the highest. When the enantiomers were administered separately, blood concentrations achieved after (-)-(R)-HCQ were higher, especially after multiple doses. These observations suggest that (-)-(R)-HCQ is preferentially concentrated by cellular components of blood. This enantioselective distribution of HCQ could be secondary to a stereoselective protein binding to plasma proteins, although a more specific binding of (-)-(R)-HCQ to blood cells cannot be ruled out. Since in whole blood (-)-(R)-HCQ is retained in cellular components, metabolism would favour the more available (+)-(S)-enantiomer.

Administration, Oral↗
PubMed1995

Stereoselective disposition of hydroxychloroquine and its metabolite in rats.

Racemic hydroxychloroquine-sulfate (HCQ-sulfate) was administered to rats orally. Groups of 9 male and 9 female rats received doses of 0, 8, 16, or 24 mg/kg/day for 6 weeks, followed by a reduction of the higher doses to 8 mg/kg/day for the duration of the study. Whole blood samples were collected at 0, 3, 6, 8, and 10 weeks, and eleven tissues were harvested after the tenth week. The concentrations and enantiomer ratios of the parent drug and three metabolites, desethylhydroxychloroquine (DHCQ), desethylchloroquine (DCQ), and bisdesethylchloroquine (BDCQ), were determined. The highest concentration of HCQ was found in the intestinal smooth muscle, and the lowest in the brain and adipose tissue. The highest concentrations of the metabolites were found in the liver, adrenals, and lung tissue. The metabolism of HCQ in the rats was found to be stereoselective with R/S > 1 for the drug and < 1 for the metabolites. Gender-specific differences in the proportions of the drug and its metabolites and their enantiomers in blood and tissue were found. Varying dosages appeared to have only a temporary influence on blood concentrations and not to effect the enantiomer ratios in blood. Only a limited number of tissues exhibited significant differences between dose groups. There were no observed differences in enantiomer ratios among the blood collection times.

Animals↗
PubMed2006

Capillary electrophoretic chiral separation of hydroxychloroquine and its metabolites in the microsomal fraction of liver homogenates.

A rapid, selective, and low-cost chiral capillary electrophoretic method was developed for the simultaneous analysis of hydroxychloroquine (HCQ) and its three chiral metabolites: desethylchloroquine (DCQ), desethylhydroxychloroquine (DHCQ), and bisdesethylchloroquine (BDCQ) in the microsomal fraction of liver homogenates. After liquid-liquid extraction using toluene as extracting solvent, the drug and metabolites were resolved on a fused-silica capillary (50 microm ID, 50 cm total length, and 42 cm effective length), using 100 mmol/L of Tris/phosphate buffer, pH 9.0 containing 1% w/v sulfated-beta-CD and 30 mg/mL hydroxypropyl-beta-CD. Detection was carried out at 220 nm. The extraction procedure was efficient in removing endogenous interferents, and low values (<or=15%) for CVs and deviation from theoretical values were demonstrated for both within-day and between-day assays. The quantitation limit was 125 ng/mL with linear response over the 125-2000 ng/mL of concentration range for all metabolites. After validation, the method was used for an in vitro metabolism study of HCQ. The major HCQ metabolite formed by microsomal enzymes was (-)-(R)-DHCQ.

Animals↗
PubMed1994

Hematologic disposition of hydroxychloroquine enantiomers.

Hydroxychloroquine (HCQ) is a racemic antiarthritic agent that has a long half-life (t1/2) in plasma and accumulates in blood cells. To study the relationships between HCQ concentrations in plasma, serum, and whole blood and to determine the optimal blood fraction to use for therapeutic drug monitoring of the drug, we studied the relative distribution of the HCQ enantiomers in various fractions of human blood under in vivo and in vitro conditions. Substantially greater concentrations of both enantiomers were found in serum as compared with plasma because of release via platelet activation. After in vitro incubations of the separated blood cells with HCQ, high concentrations of both enantiomers were found in leukocytes, and low concentrations in erythrocytes and platelets; the R:S ratio in vitro was near unity in all of the cells examined. Unlike the in vitro cellular uptake, the concentrations of HCQ in vivo were significantly lower and stereoselective (R:S ratio = 2). There was almost no drug in the polymorphonuclear cells (PMN) in vivo, despite a substantial uptake in vitro after incubation of separated cells. The enantiomeric (R:S) ratio in the urinary excretion of the enantiomers was significantly correlated with that in plasma. The plasma-protein binding of the enantiomers was stereoselective and complimented the cellular uptake findings; the unbound fraction was dependent on the plasma concentrations of alpha 1-acid glycoprotein, but not albumin. Although concentrations in whole blood correlated well with those in lymphocytes and monocytes (the proposed site of HCQ action), stronger correlations were found between concentrations in serum and in the mononuclear cells.

Adult↗
PubMed1995

Serum soluble interleukin-2 receptor levels in rheumatoid arthritis: effect of methotrexate, sulphasalazine and hydroxychloroquine therapy.

The aim of this study was to assess the correlations of the serum soluble interleukin 2 receptor (sIL-2R) concentrations with disease activity parameters and response to treatment with second line drugs in patients with rheumatoid arthritis (RA). Sixty-seven patients with active disease completed a 24-week, open, randomized study of methotrexate (MTX) versus sulphasalazine (SSZ) or hydroxychloroquine (HCQ). Serum sIL-2R levels were evaluated before entry and after 24 weeks by ELISA. Serum sIL-2R were significantly higher in RA patients than in controls (P = 0.0001) and correlated significantly only with erythrocyte sedimentation rate (P = 0.03) and with Chronic Arthritis Systemic Index (P = 0.01) at study entry. No correlation was found between serum sIL-2R and other laboratory and clinical indices of disease activity. After 24 weeks of treatment no differences in serum sIL-2R in comparison with basal levels were found in either responding or in non-responding patients, although the mean reduction of sIL-2R was more marked in the MTX-treated cohort than in the HCQ and SSZ-treated groups. These data suggest that in RA the measurement of sIL-2R should be used with caution as an isolated index of disease activity and that it is not a useful marker of response to treatment with second line drugs.

Adult↗
PubMed1997

Toxicity profile of dual methotrexate combinations with gold, hydroxychloroquine, sulphasalazine and minocycline in rheumatoid arthritis patients.

The purpose of the present study was to evaluate the toxicity and tolerability of methotrexate (MTX)/gold (G; group 1) combination therapy as compared to other MTX combinations [MTX with hydroxychloroquine (HCQ; group 2), MTX with sulphasalazine (SASP; group 3) and MTX with minocycline (MNC; group 4)]. The hospital records of 127 consecutive rheumatoid arthritis (RA) patients who were treated with these combinations during a period of 24 months were retrospectively reviewed. The toxicity and tolerability of the MTX/G combination was compared to the other dual MTX combinations and also to MTX alone using data previously reported by us on 126 RA patients treated with single MTX therapy. The mean exposure time to treatment was 16 months in group 1 and 13 months in the other dual MTX combinations. During the period of follow-up, the combination was stopped in 22 out of 42 patients in group 1 (52%) in comparison with 54 patients out of 86 patients (63%) in the other dual regimen groups. The discontinuation rate was highest in group 4 (due to side effects and lack of compliance) and this was statistically significant in comparison with group 1. The proportion of adverse events was lowest in group 1 (14%) and highest in groups 3 and 4 (25%). Side effects were reversible and comparable with those of MTX alone (23%). No fatal or life-threatening side effects were recorded during any of these MTX combination therapies. We concluded that the combinations of MTX with G, HCQ, SASP and MNC in RA were relatively well tolerated. No increase in toxicity compared with MTX alone was observed. The lowest rate of side effects was noted in group 1, while group 4 presented the highest discontinuation rate.

Adult↗
PubMed2003

An open, randomized comparison study of cyclosporine A, cyclosporine A + methotrexate and cyclosporine A + hydroxychloroquine in the treatment of early severe rheumatoid arthritis.

PURPOSE: To determine whether a regimen of cyclosporine (CSA) and methotrexate (MTX), or CSA and hydroxychloroquine (HCQ) introduced in early rheumatoid arthritis (RA) can produce a significant improvement in clinical outcome and/or retard radiographic damage in comparison with standard monotherapy with CSA alone. METHODS: One hundred five patients with active RA of less than 36 months duration, who had never previously been treated with immunosuppressive agents, were included in a 12-month, multi-center, open, randomized trial. Patients who fulfilled the criteria for early severe RA were randomized to receive either combination therapy (CSA + MTX n = 34, CSA + HCQ n = 35) or CSA alone (n = 36). RESULTS: CSA + MTX was more effective than the other two treatment groups in controlling RA symptoms. CSA+MTX did not show a significant radiographic progression according to Larsen-Dale (0.90 +/- 3.89 compared to baseline values, P > 0.05); moreover, patients treated with CSA alone or CSA+HCQ showed a significant worsening of Larsen-Dale score (2.91 +/- 5.99 and 2.97 +/- 4.28 respectively vs baseline values, P < 0.05), although not significant when compared with the CSA + HCQ group (P = 0.56 and 0.39, respectively). CONCLUSIONS: This trial indicated that CSA+MTX was more effective than the other two treatments in improving clinical data and inhibiting radiographic progression, although the differences were not significant in this relatively small study. However, the difference was significant in favor of CSA + MTX regarding ACR 50% response.

Antirheumatic Agents↗
PubMed2000

Hydroxychloroquine ototoxicity in a patient with rheumatoid arthritis.

We report a case of reversible sensorineural hearing loss due to hydroxychloroquine (HQ) treatment. The patient was a 34-year-old woman with 1 year of rheumatoid arthritis (RA). She developed reversible hearing loss after 5 months of HQ treatment. Sensorineural deafness has previously been reported with chloroquine treatment, but this is the first report of ototoxicity associated with HQ in RA.

Adult↗
PubMed2007

In vivo confocal microscopy in hydroxychloroquine-induced keratopathy.

BACKGROUND: Vortex keratopathy, arising as a side effect of several medications, is characterized by golden-brown deposits in the cornea. METHODS: A 41-year-old woman treated for sarcoidosis with hydroxychloroquine therapy and suffering from vortex keratopathy was examined by in vivo confocal microscopy. Scans of both corneas were performed. RESULTS: By slit lamp examination, the left but not the right eye showed a golden-brown deposit throughout the cornea. In vivo confocal microscopy revealed the presence of highly reflective, dot-like intracellular inclusions concentrated in the basal epithelial layer. They were also detected within the anterior and posterior stroma, but not within the endothelium. In regions of the anterior stroma, devoid of inclusions, hyperreflective ramified keratocytes were observed, forming an extended interconnecting network. CONCLUSION: In addition to the granular deposits, in vivo confocal microscopy revealed hyperreflective, possibly phagocytic keratocytes.

Adult↗
PubMed2006

Severe acute hepatitis related to hydroxychloroquine in a woman with mixed connective tissue disease.

Antimalarial drugs are used for the control of mild manifestations of autoimmune diseases due to their low toxicity. Hydroxychloroquine (HCQ), a alpha-hydroxylated derivative of chloroquine, is usually preferred because of its higher tolerability. Mild and unspecific gastrointestinal symptoms are the main secondary effects related to HCQ use. Less than 1% of subjects show liver enzyme increase, although the percentage can be as high as 50% in subjects with chronic liver disease. A woman with mixed connective tissue disease who developed a reversible acute hepatitis shortly after the initiation of low-dose HCQ is presented. Two previous cases of patients with acute liver failure have previously been published. All three cases have been reported in the absence of previous liver disease. It seems to be a dose-dependent, idiosyncratic, and molecule-specific toxic effect and must be considered, taking into account the potential bad prognosis.

Acute Disease↗
PubMed2000

Combination therapy with hydroxychloroquine, gold sodium thiomalate and methotrexate in early rheumatoid arthritis. An open 3-year study.

During recent years, aggressive therapeutic approaches have been proposed in order to control the Rheumatoid Arthritis (RA) activity and to avoid joint destruction. Here we report the results of an open 3-year trial on the combination of three second-line drugs, hydroxychloroquine (HCQ), methotrexate (MTX) and gold sodium thiomalate (GST), in early active RA. Four men and 17 women were enrolled in the study and were treated during the first year with HCQ 400 mg/day, GST 50 mg/week and oral MTX 7.5 mg/week; during the second and the third years the doses of HCQ and MTX were reduced to 200 mg/day and 5 mg/week, respectively; the interval between the GST injections was progressively increased until 4 weeks. Prednisone at an initial dose not higher than 10 mg/day was associated. Sulindac was allowed. Eight patients left the study because of side-effects, 2 patients abandoned the study, 12 patients compleated the 3 years of treatment. We obtained a significant and early amelioration of both clinical and laboratory parameters during the first year; in the two subsequent years the positive results were maintained. In our opinion the most significant result is the absence of anatomical progression in 10 out of 12 patients, even if a more prolonged observation is necessary to obtain more reliable data.

Adult↗
PubMed2002

An in vitro study of the susceptibility of mobile and cystic forms of Borrelia burgdorferi to hydroxychloroquine.

In this work the susceptibility of mobile and cystic forms of Borrelia burgdorferi to hydroxychloroquine (HCQ) was studied. The minimal bactericidal concentration (MBC) of HCQ against the mobile spirochetes was > 32 microg/ml at 37 degrees C, and > 128 microg/ml at 30 degrees C. Incubation with HCQ significantly reduced the conversion of mobile spirochetes to cystic forms. When incubated at 37 degrees C, the MBC for young biologically active cysts (1-day old) was > 8 microg/ml, but it was > 32 microg/ml for old cysts (1-week old). Acridine orange staining, dark-field microscopy and transmission electron microscopy revealed that the contents of the cysts were partly degraded when the concentration of HCQ was > or = MBC. At high concentrations of HCQ (256 microg/ml) about 95% of the cysts were ruptured. When the concentration of HCQ was > or = MBC, core structures did not develop inside the cysts, and the amount of RNA in these cysts decreased significantly. Spirochetal structures inside the cysts dissolved in the presence of high concentrations of HCQ. When the concentration of HCQ was > or = MBC, the core structures inside the cysts were eliminated. These observations may be valuable in the treatment of resistant infections caused by B. burgdorferi, and suggest that a combination of HCQ and a macrolide antibiotic could eradicate both cystic and mobile forms of B. burgdorferi.

Antimalarials↗
PubMed1990

Cholesterol-lowering effect of hydroxychloroquine in patients with rheumatic disease: reversal of deleterious effects of steroids on lipids.

PURPOSE: The effects of hydroxychloroquine (HCQ) on serum levels of cholesterol, triglycerides, and high- (HDL) and low-density lipoprotein (LDL) were studied in patients with rheumatoid arthritis or systemic lupus erythematosus. PATIENTS AND METHODS: A total of 155 women were divided into the following treatment groups: Group A: patients taking HCQ and no steroids (n = 58); Group B: patients taking steroids and no HCQ (n = 35); Group C: patients receiving both HCQ and steroids (n = 18); and Group D: patients receiving neither HCQ nor steroids (n = 44). RESULTS: HCQ therapy had a high statistical association with low serum levels of cholesterol (181 mg/dL; p = 0.0006), triglycerides (106 mg/dL; p = 0.0459), and LDL (101 mg/dL; p = 0.0004), irrespective of concomitant steroid administration. The HCQ-treated group (A) had lower cholesterol (181 mg/dL; p = 0.0039) and LDL (101 mg/dL; p = 0.007) levels than those receiving neither HCQ nor steroids (205 mg/dL) and 128 mg/dL) (Group D). No HDL differences were observed. CONCLUSION: The effects of HCQ do not appear to be due to changes in diet or weight, and the drug was well tolerated. Although the mechanism of cholesterol lowering by HCQ is not known, this drug deserves further investigation for its lipid-lowering properties.

Adolescent↗
PubMed1986

Differential effects of mepacrine, chloroquine and hydroxychloroquine on superoxide anion generation, phospholipid methylation and arachidonic acid release by human blood monocytes.

The 4-aminoquinolines chloroquine (CQ) and hydroxychloroquine (HCQ), and previously the 9-aminoacridine mepacrine (quinacrine) (MP), have been widely used in the treatment of inflammatory disorders such as rheumatoid arthritis and systemic lupus erythematosus. Their effects are believed to be mediated through phagocytic cells but the precise biochemical basis remains uncertain. We have investigated the effects of these drugs on monocyte superoxide anion (SO) generation elicited by 5 different stimuli-opsonised zymosan (STZ), FMLP, A23187, TPA and fluoride--and sought correlations with effects on two processes which have been linked with monocyte activation, namely arachidonate (AA) release and transmethylation of phosphatidyl ethanolamine (PE) to phosphatidylcholine (PC). In all experiments conditions were adjusted to achieve leucocyte concentrations of drug comparable to those found during in vivo therapy. Neither CQ nor HCQ had any marked effect on SO release induced by TPA, A23187 or fluoride ion, excluding a significant effect on protein kinase C (PKC), calmodulin-dependent kinase(s) or the membrane-bound, superoxide generating NADP(H) oxidase. In contrast MP inhibited the response to TPA and A23187. Each drug also had different effects on surface receptor-dependent responses; thus HCQ inhibited FMLP- but not STZ-induced SO release, whereas CQ and MP inhibited the response to both stimuli. Each drug also displayed different effects on AA release and phospholipid (PL)-methylation; MP and HCQ, but not CQ, inhibited STZ-stimulated AA release while MP and CQ but not HCQ inhibited basal rates of PL-methylation in mononuclear cells (MNC). However, only MP inhibited PL-methylation in an enriched monocyte population. We conclude that despite their close structural similarity, MP, CQ and HCQ each have different metabolic effects and their actions cannot simply be attributed to inhibition of lysosomal functions. Other possible mechanisms of action are discussed. The selective effects of each drug also provide further evidence for multiple pathways of monocyte activation.

Arachidonic Acid↗
PubMed1991

Kinetics and thermodynamics of chloroquine and hydroxychloroquine transport across the human erythrocyte membrane.

Chloroquine (CQ) and hydroxychloroquine (HCQ) have almost identical molecular volumes but showed very different permeability characteristics. The permeability coefficient for the unionised species of CQ (2.0 cm/sec at 25 degrees) was about fifty times that of HCQ (0.039 cm/sec at 25 degrees), but the apparent activation energy for transport (85 kJ/mol for CQ, 81 kJ/mol for HCQ) was almost identical for the two drugs. The partition coefficient of CQ into various organic solvents was much higher than for HCQ, but the different permeability behaviour cannot be quantitatively explained by partitioning behaviour into hexane or octanol, two solvents commonly used to mimic the membrane interior. A comparison of permeability and partitioning characteristics suggests that the barrier phase for these drugs within the membrane can be modelled by a mixed solvent of 5% octanol in hexane. The results suggest that interactions with hydrogen bonding groups within the membrane are important in the membrane transport of these drugs, and that the membrane does not behave functionally as a simple hydrocarbon barrier.

Biological Transport↗
PubMed1984

The hypocomplementemic urticarial-vasculitis syndrome: therapeutic response to hydroxychloroquine.

We report a patient with hypocomplementemic urticarial-vasculitis syndrome. This case illustrates the continuum between urticaria and purpura characteristic of hypocomplementemic urticarial-vasculitis syndrome. Clq precipitin was demonstrated in the patient's serum and in the diethylaminoethylcellulose-ion exchange fraction containing only IgG. A skin biopsy specimen of urticarial and purpuric lesions demonstrated leukocytoclastic vasculitis and granular deposition of C3 and Clq in the basement membrane with IgA, IgM, C3, and Clq in postcapillary venules. Serial total hemolytic complement activity and Clq determinations were performed, and the response to several treatment regimens is presented. Symptomatic and serologic improvement was observed only with hydroxychloroquine.

Adult↗
PubMedDate not supplied

Hydroxychloroquine treatment of patients with human immunodeficiency virus type 1.

Hydroxychloroquine (HCQ), an antimalarial agent used to treat patients with autoimmune diseases, has been shown to suppress human immunodeficiency virus type 1 (HIV-1) replication in vitro in T cells and monocytes by inhibiting posttranscriptional modification of the virus. These in vitro observations have been expanded into an in vivo study of HCQ as a potential anti-HIV-1 agent in HIV-1-infected patients. A randomized, double-blind, placebo-controlled clinical trial was conducted in 40 asymptomatic HIV-1-infected patients who had CD4+ counts between 200 and 500 cells/mm3. Patients were randomly assigned to receive either HCQ 800 mg/d or placebo for 8 weeks. Virologic and immunologic parameters, including HIV-1 ribonucleic acid (RNA) via use of polymerase chain reaction, viral culture, antigen and mitogen responses, and proinflammatory cytokine levels were measured at the beginning and end of the study. The amount of recoverable HIV-1 RNA in plasma declined significantly in the HCQ group over the 8-week period (P = 0.022), while it increased in the placebo group. The percentage of CD4+ T cells remained stable in the HCQ-treated group (18.1 +/- 9.2% before treatment vs 18.6 +/- 10.5% after treatment) and fell significantly in the placebo group (21 +/- 7% before treatment vs 19.3 +/- 6.3% after treatment; P = 0.032). However, this was not reflected as a change in absolute CD4+ counts for either group (HCQ, 262.8 +/- 166 cells/mm3 vs 251 +/- 163 cells/mm3; placebo, 312 +/- 121 cells/mm3 vs 321 +/- 124 cells/mm3). Mitogen- and antigen-specific responses remained constant in the HCQ group while T cell proliferative responses to Candida decreased in the placebo group (4.8 +/- 3.6 x 10(3) SI [stimulation index] vs 3.0 +/- 3.0 x 10(3) SI; P = 0.032). Lastly, serum interleukin 6 levels declined in the HCQ group (14.3 +/- 13.5 U/mL vs 12.0 +/- 16.7 U/mL; P = 0.023) but not in the placebo group (11.3 +/- 8.8 U/mL vs 7.0 +/- 11.7 U/mL); this was coincident with a decrease in serum immunoglobulin (Ig)G (2563 +/- 1352 mg/mL vs 2307 +/- 1372 mg/dL; P = 0.032), compared with the placebo group (2733 +/- 1473 mg/dL vs 2709 +/- 1501 mg/dL). No other parameters, including serum p24 and beta-2 microglobulin levels, were altered by HCQ therapy. HCQ thus may be useful in the treatment of patients with HIV-1 infection.

Acquired Immunodeficiency Syndrome↗