Bioavailability of hydroxychloroquine tablets in healthy volunteers

Early reduction in total cholesterol to high-density lipoprotein cholesterol ratio predicts hydroxychloroquine efficacy in treating IgA nephropathy

BACKGROUND

Hydroxychloroquine (HCQ) effectively improves lipid levels in patients with autoimmune diseases. This study aimed to examine the effect of HCQ on lipid profiles in patients with immunoglobulin A (IgA) nephropathy (IgAN) and determine whether alterations in lipid profiles can predict the efficacy of HCQ.

METHODS

This study retrospectively analyzed 77 patients, and the total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) decline rate after 3 months of HCQ treatment was selected as a predictor based on receiver operating curve analysis. Patients were then divided into low and high TC/HDL-C decline rate groups based on the optimal cutoff value. The Cox proportional hazard model and Kaplan-Meier curve were used to evaluate the value of the TC/HDL-C decline rate in predicting the efficacy of HCQ in patients with IgAN.

RESULTS

Patients in the high TC/HDL-C decline rate group with ≥50% decrease in proteinuria from baseline experienced a significant improvement during the follow-up. Kaplan-Meier analysis revealed that a high TC/HDL-C decline rate was strongly associated with a higher proteinuria reduction rate in patients with IgAN. Furthermore, multivariate Cox analysis indicated that a higher reduction in the TC/HDL-C ratio (hazard ratio: 2.314; 95% confidence interval: 1.234-4.340; p = 0.009) was an independent predictive indicator for achieving ≥50% reduction in proteinuria with HCQ therapy in IgAN.

CONCLUSION

HCQ effectively improves lipid profiles in patients with IgAN, and an early decrease in the TC/HDL-C ratio serves as a predictor of better outcomes in patients treated with HCQ.

Target in Sight: A Comprehensive Review of Hydroxychloroquine-Induced Bull's Eye Maculopathy

Purpose of Review

We review the latest screening and diagnostic techniques, and the most recent recommendations on the management of hydroxychloroquine retinopathy.

Recent Findings

Hydroxychloroquine (HCQ) has been shown to cause retinal toxicity in a dose-dependent fashion. Early diagnosis is critical as the resultant retinopathy is not reversible. New imaging modalities, such as adaptive optics (AO), microperimetry, and retro-mode imaging, may show promise in the timely diagnosis of HCQ retinopathy.

Summary

Automated visual fields and spectral-domain optical coherence tomography (SD-OCT) are the primary tests used in routine screening for HCQ retinopathy, but fundus autofluorescence (FAF) and multifocal electroretinogram (mfERG) have also been shown to be useful. A baseline ophthalmologic examination is recommended in all patients beginning long-term hydroxychloroquine therapy within the first year of starting therapy. Automated visual fields and SD-OCT should be included during this baseline exam in patients with pre-existing macular conditions. Afterwards, annual screening can be deferred for the first 5 years of HCQ treatment unless the patient has a major risk factor.

Risk Factors for Hydroxychloroquine Retinopathy and Its Subtypes

Importance

The major toxic effect of hydroxychloroquine is retinopathy. Thus, current guidelines recommend limiting the dose and screening annually for retinopathy among all long-term users, but individual patient factors may be associated with retinopathy risk.

Objective

To identify risk factors beyond hydroxychloroquine dose and duration of use for hydroxychloroquine retinopathy.

Design, Setting, and Participants

This cohort study of 4677 patients in the Kaiser Permanente Northern California integrated health network who initiated hydroxychloroquine, continued treatment, and underwent retinopathy screening after 5 years of use was conducted from July 1, 1997, to December 31, 2020, with up to 15 years of follow-up. Statistical analysis was performed in August 2023.

Exposure

Candidate risk factors included age at hydroxychloroquine initiation, sex, race and ethnicity, indications, chronic kidney disease (CKD), liver disease, diabetes, tamoxifen use, and medications that interact with hydroxychloroquine metabolism. Hydroxychloroquine dose was assessed from pharmacy dispensing records.

Main Outcome and Measures

Incident hydroxychloroquine retinopathy was adjudicated from masked review of guideline-recommended screening studies and classified as parafoveal or pericentral pattern. Multivariable Cox proportional hazards regression was used to assess potential risk factors for hydroxychloroquine retinopathy within 15 years of initiation.

Results

Of 4677 long-term hydroxychloroquine users (mean [SD] age at initiation, 52.4 [14.1] years; 3877 women [82.9%]), 125 patients developed hydroxychloroquine retinopathy within 15 years (102 parafoveal, 23 pericentral). Older age at time of hydroxychloroquine initiation was associated with retinopathy risk, with adjusted hazard ratios (HRs) of 2.48 (95% CI, 1.28-4.78) for those aged 45 to 54 years, 3.82 (95% CI, 2.05-7.14) for those aged 55 to 64 years, and 5.68 (95% CI, 2.99-10.79) for those aged 65 years or older compared with those younger than 45 years. The risk of retinopathy was higher among females than males (HR, 3.83 [95% CI, 1.86-7.89]), among patients with CKD stage 3 or greater (HR, 1.95 [95% CI, 1.25-3.04]), and among individuals with tamoxifen use (HR, 3.43 [95% CI, 1.08-10.89]). The likelihood of pericentral retinopathy was higher among Asian patients (HR, 15.02 [95% CI, 4.82-46.87]) and Black patients (HR, 5.51 [95% CI, 1.22-24.97]) compared with non-Hispanic White patients.

Conclusions and Relevance

This study suggests that increasing age, female sex, CKD stage 3 or greater, and tamoxifen use were associated with a higher risk of hydroxychloroquine retinopathy, whereas being younger than 45 years at hydroxychloroquine initiation and male sex were associated with a lower risk. Race and ethnicity were also associated with the pattern of retinopathy. These factors should be incorporated into hydroxychloroquine dosing decisions.

An Explanation of Why Dose-Corrected Area Under the Curve for Alternate Administration Routes Can Be Greater than for Intravenous Dosing

It is generally believed that bioavailability (F) calculated based on systemic concentration area under the curve (AUC) measurements cannot exceed 1.0, yet some published studies report this inconsistency. We teach and believe, based on differential equation derivations, that rate of absorption has no influence on measured systemic clearance following an oral dose, i.e., determined as available dose divided by AUC. Previously, it was thought that any difference in calculating F from urine data versus that from systemic concentration AUC data was due to the inability to accurately measure urine data. A PubMed literature search for drugs exhibiting F > 1.0 and studies for which F was measured using both AUC and urinary excretion dose-corrected analyses yielded data for 35 drugs. We show and explain, using Kirchhoff's Laws, that these universally held concepts concerning bioavailability may not be valid in all situations. Bioavailability, determined using systemic concentration measurements, for many drugs may be overestimated since AUC reflects not only systemic elimination but also absorption rate characteristics, which is most easily seen for renal clearance measures. Clearance of drug from the absorption site must be significantly greater than clearance following an iv bolus dose for F(AUC) to correctly correspond with F(urine). The primary purpose of this paper is to demonstrate that studies resulting in F > 1.0 and/or greater systemic vs urine bioavailability predictions may be accurate. Importantly, these explications have no significant impact on current regulatory guidance for bioequivalence testing, nor on the use of exposure (AUC) measures in making drug dosing decisions.

The presumable effects of hydroxychloroquine and its metabolites in the treatment of systemic lupus erythematosus

OBJECTIVE

Hydroxychloroquine (HCQ) is an essential drug in the treatment of systemic lupus erythematosus (SLE). This study aimed to detect the concentrations of HCQ and its metabolites from peripheral blood of SLE patients and to investigate the relationship between those concentrations and SLE disease activity.

METHODS

176 SLE patients treated with HCQ were enrolled in this study. The concentrations of HCQ and its metabolites in their peripheral blood were measured by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Patients' disease activity was evaluated with the systemic lupus erythematosus disease activity index (SLEDAI). The variables between different concentrations or treatments were statistically analyzed. Linear regression was employed to explore relationships between the concentrations of HCQ and its metabolites with the disease activity.

RESULTS

The SLEDAI was lower in patients with higher concentrations of HCQ, desethylhydroxychloroquine (DHCQ), and desethylchloroquine (DCQ) (P = 0.024, P = 0.018, and P = 0.003, respectively). There were no significant differences in SLEDAI and the concentrations of HCQ and its metabolites among groups with different treatments (P > 0.05). After adjusting age, gender, disease duration, HCQ dose adjusted to actual body weight, and glucocorticoid (GC) dose, the SLEDAI was negatively correlated with the concentrations of HCQ, DHCQ, DCQ and bisdesethylchloroquine (BDCQ) (P = 0.007, P = 0.011, P = 0.029, and P = 0.008, respectively). After grouping analysis, in patients treated with HCQ and GC, the SLEDAI was negatively correlated with concentrations of HCQ, DHCQ and BDCQ (P = 0.011, P = 0.035, and P = 0.036, respectively).

CONCLUSIONS

The concentrations of HCQ and metabolites were correlated with the SLE disease activity after adjusting possible confounding factors, indicating that HCQ and its metabolites might play certain immunoregulatory roles in SLE treatment. Moreover, GC might have a synergistic effect with HCQ. It is helpful in clinical management and follow-up to monitor the concentrations of HCQ and its metabolites in SLE patients.

In Vitro and in Vivo Antimalarial Activity, Cytotoxicity and Phytochemical HRMS2 Profile of Plants from the Western Pará State, Brazilian Amazonia

Ethnopharmacology and botanical taxonomy are valid criteria used to selecting plants for antimalarial bioprospection purposes. Based on these two criteria, ethanol extracts of 11 plants from Santarém City vicinities, Western Pará State, Brazilian Amazonia, had their in vitro antiplasmodial activity against chloroquine-resistant Plasmodium falciparum (W2 clone) assessed by the PfLDH method, whereas their cytotoxicity to HepG2-A16 cells was assessed through MTT assay. Acmella oleracea, Siparuna krukovii and Trema micrantha extracts disclosed the highest rate of parasite growth inhibition (90 %) in screening tests. In vivo antimalarial assays were conducted with these extracts against Plasmodium berghei (NK 65 strain) infected mice. Inhibition rate of parasite multiplication ranged from 41.4 % to 60.9 % at the lowest extract dose (25 mg/kg). HPLC-ESI-HRMS2 analyses allowed the putative identification of alkylamides, fatty acids, flavonoid glycosides and alkaloids in ethanol extracts deriving from these three plant species. Results pointed towards A. oleracea flowers ethanol extract as the most promising potential candidate to preclinical studies aiming the development of antimalarial phytomedicine.

Hydroxychloroquine in nephrology: current status and future directions

Hydroxychloroquine is one of the oldest disease-modifying anti-rheumatic drugs in clinical use. The drug interferes with lysosomal activity and antigen presentation, inhibits autophagy, and decreases transcription of pro-inflammatory cytokines. Owing to its immunomodulatory, anti-inflammatory, anti-thrombotic effect, hydroxychloroquine has been an integral part of therapy for systemic lupus erythematosus and lupus nephritis for several decades. The therapeutic versatility of hydroxychloroquine has led to repurposing it for other clinical conditions, with recent studies showing reduction in proteinuria in IgA nephropathy. Research is also underway to investigate the efficacy of hydroxychloroquine in primary membranous nephropathy, Alport's syndrome, systemic vasculitis, anti-GBM disease, acute kidney injury and for cardiovascular risk reduction in chronic kidney disease. Hydroxychloroquine is well-tolerated, inexpensive, and widely available and therefore, should its indications expand in the future, it would certainly be welcomed. However, clinicians should be aware of the risk of irreversible and progressive retinal toxicity and rarely, cardiomyopathy. Monitoring hydroxychloroquine levels in blood appears to be a promising tool to evaluate compliance, individualize the dose and reduce the risk of retinal toxicity, although this is not yet standard clinical practice. In this review, we discuss the existing knowledge regarding the mechanism of action of hydroxychloroquine, its utility in lupus nephritis and other kidney diseases, the main adverse effects and the evidence gaps that need to be addressed in future research. Created with Biorender.com. HCQ, hydroxychloroquine; GBM, glomerular basement membrane; mDC, myeloid dendritic cell; MHC, major histocompatibility complex; TLR, toll-like receptor.

Protective effect of hydroxychloroquine on infections in patients with systemic lupus erythematosus: an observational study using the LUNA registry

Objectives

Infection is a leading cause of death in patients with systemic lupus erythematosus (SLE). Alt hough hydroxychloroquine (HCQ) has been reported to inhibit infection, evidence from Asian populations remains insufficient. We investigated this effect in Japanese SLE patients.

Methods

Data from the Lupus Registry of Nationwide Institutions were used in this study. The patients were ≥20 years old and met the American College of Rheumatology (ACR) classification criteria revised in 1997. We defined "severe infections" as those requiring hospitalization. We analyzed the HCQ's effect on infection suppression using a generalized estimating equation (GEE) logistic regression model as the primary endpoint and performed a survival analysis for the duration until the first severe infection.

Results

Data from 925 patients were used (median age, 45 [interquartile range 35-57] years; female, 88.1%). GEE analysis revealed that severe infections were significantly associated with glucocorticoid dose (odds ratio [OR] 1.968 [95% confidence interval, 1.379-2.810], p<0.001), immunosuppressants (OR 1.561 [1.025-2.380], p=0.038), and baseline age (OR 1.043 [1.027-1.060], p<0.001). HCQ tended to suppress severe infections, although not significantly (OR 0.590 [0.329-1.058], p=0.077). Survival time analysis revealed a lower incidence of severe infections in the HCQ group than in the non-HCQ group (p<0.001). In a Cox proportional hazards model, baseline age (hazard ratio [HR] 1.029 [1.009-1.050], p=0.005) and HCQ (HR 0.322 [0.142-0.728], p=0.006) were significantly related to incidence.

Conclusion

HCQ may help extend the time until the occurrence of infection complications and tends to decrease infection rates.

Pharmacokinetics of hydroxychloroquine in Japanese systemic lupus erythematosus patients with renal impairment

OBJECTIVES

Reduction of the hydroxychloroquine (HCQ) dosage is recommended in systemic lupus erythematosus (SLE) patients with renal impairment, but a pharmacokinetics (PK) study of patients with renal impairment has not yet been performed.

METHODS

We investigated the PK of both single and multiple doses of HCQ and its metabolites in SLE patients with renal impairment who newly started HCQ at a daily dose of 300 mg based on an ideal body weight dosage of 6.5 mg/kg. Population PK analysis was performed using a non-linear mixed-effects model.

RESULTS

In total, 219 samples from 21 patients were analysed. The PK of HCQ in blood after single and multiple oral administrations followed the two-compartment model. At steady state, the concentration ratio of HCQ to each metabolite was HCQ:desethylhydroxychloroquine:desethylchloroquine:bisdesethylchloroquine = 1:0.28:0.1:0.06. The HCQ concentration correlated positively with that of each metabolite. The estimated values (relative standard error) of the population PK parameters were the total clearance at 110 l/h (31%) and a central volume of distribution of 398 l (19%). Co-administration of prednisolone and age, but not renal impairment, were factors affecting the total clearance of HCQ.

CONCLUSIONS

From the PK perspective, a dosage reduction is unnecessary in SLE patients with impaired renal function.

A linked physiologically based pharmacokinetic model for hydroxychloroquine and metabolite desethylhydroxychloroquine in SARS-CoV-2(-)/(+) populations

Hydroxychloroquine (HCQ) is Food and Drug Administration (FDA)-approved for malaria, systemic and chronic discoid lupus erythematosus, and rheumatoid arthritis. Because HCQ has a proposed multimodal mechanism of action and a well-established safety profile, it is often investigated as a repurposed therapeutic for a range of indications. There is a large degree of uncertainty in HCQ pharmacokinetic (PK) parameters which complicates dose selection when investigating its use in new disease states. Complications with HCQ dose selection emerged as multiple clinical trials investigated HCQ as a potential therapeutic in the early stages of the COVID-19 pandemic. In addition to uncertainty in baseline HCQ PK parameters, it was not clear if disease-related consequences of SARS-CoV-2 infection/COVID-19 would be expected to impact the PK of HCQ and its primary metabolite desethylhydroxychloroquine (DHCQ). To address the question whether SARS-CoV-2 infection/COVID-19 impacted HCQ and DHCQ PK, dried blood spot samples were collected from SARS-CoV-2(-)/(+) participants administered HCQ. When a previously published physiologically based pharmacokinetic (PBPK) model was used to fit the data, the variability in exposure of HCQ and DHCQ was not adequately captured and DHCQ concentrations were overestimated. Improvements to the previous PBPK model were made by incorporating the known range of blood to plasma concentration ratios (B/P) for each compound, adjusting HCQ and DHCQ distribution settings, and optimizing DHCQ clearance. The final PBPK model adequately captured the HCQ and DHCQ concentrations observed in SARS-CoV-2(-)/(+)participants, and incorporating COVID-19-associated changes in cytochrome P450 activity did not further improve model performance for the SARS-CoV-2(+) population.

Hydroxychloroquine-induced Retinal Toxicity

Long-term use of hydroxychloroquine can cause retinopathy, which may result in severe and progressive visual loss. In the past decade, hydroxychloroquine use has markedly increased and modern retinal imaging techniques have enabled the detection of early, pre-symptomatic disease. As a consequence, the prevalence of retinal toxicity in long-term hydroxychloroquine users is known to be higher than was previously estimated. The pathophysiology of the retinopathy is incompletely characterised, although significant advances have been made in understanding the disease from clinical imaging studies. Hydroxychloroquine retinopathy elicits sufficient public health concern to justify the implementation of retinopathy screening programs for patients at risk. Here, we describe the historical background of hydroxychloroquine retinopathy and summarize its current understanding. We review the utility and limitations of each of the mainstream diagnostic tests used to detect hydroxychloroquine retinopathy. The key considerations towards a consensus on the definition of hydroxychloroquine retinopathy are outlined in the context of what is known of the natural history of the disease. We compare the current screening recommendations for hydroxychloroquine retinopathy, identifying where additional evidence is required, and the management of proven cases of toxicity. Finally, we highlight the areas for further investigation, which may further reduce the risk of visual loss in hydroxychloroquine users.

Predicting Hydroxychloroquine Clearance in Healthy and Diseased Populations Using a Physiologically Based Pharmacokinetic Approach

Hydroxychloroquine (HCQ), a congener of chloroquine, is widely used in prophylaxis and the treatment of malaria, and also as a cure for rheumatoid arthritis, systemic lupus erythematosus, and various other diseases. Physiologically based pharmacokinetic modeling (PBPK) has attracted great interest in the past few years in predicting drug pharmacokinetics (PK). This study focuses on predicting the PK of HCQ in the healthy population and extrapolating it to the diseased populations, i.e., liver cirrhosis and chronic kidney disease (CKD), utilizing a systematically built whole-body PBPK model. The time vs. concentration profiles and drug-related parameters were obtained from the literature after a laborious search and in turn were integrated into PK-Sim software for designing healthy intravenous, oral, and diseased models. The model's evaluation was performed using observed-to-predicted ratios (Robs/Rpre) and visual predictive checks within a 2-fold error range. The healthy model was then extrapolated to liver cirrhosis and CKD populations after incorporating various disease-specific pathophysiological changes. Box-whisker plots showed an increase in AUC_0-t in liver cirrhosis, whereas a decrease in AUC_0-t was seen in the CKD population. These model predictions may assist clinicians in adjusting the administered HCQ doses in patients with different degrees of hepatic and renal impairment.

Hydroxychloroquine lowers Alzheimer's disease and related dementias risk and rescues molecular phenotypes related to Alzheimer's disease

We recently nominated cytokine signaling through the Janus-kinase-signal transducer and activator of transcription (JAK/STAT) pathway as a potential AD drug target. As hydroxychloroquine (HCQ) has recently been shown to inactivate STAT3, we hypothesized that it may impact AD pathogenesis and risk. Among 109,124 rheumatoid arthritis patients from routine clinical care, HCQ initiation was associated with a lower risk of incident AD compared to methotrexate initiation across 4 alternative analyses schemes addressing specific types of biases including informative censoring, reverse causality, and outcome misclassification (hazard ratio [95% confidence interval] of 0.92 [0.83-1.00], 0.87 [0.81-0.93], 0.84 [0.76-0.93], and 0.87 [0.75-1.01]). We additionally show that HCQ exerts dose-dependent effects on late long-term potentiation (LTP) and rescues impaired hippocampal synaptic plasticity prior to significant accumulation of amyloid plaques and neurodegeneration in APP/PS1 mice. Additionally, HCQ treatment enhances microglial clearance of Aβ_1-42, lowers neuroinflammation, and reduces tau phosphorylation in cell culture-based phenotypic assays. Finally, we show that HCQ inactivates STAT3 in microglia, neurons, and astrocytes suggesting a plausible mechanism associated with its observed effects on AD pathogenesis. HCQ, a relatively safe and inexpensive drug in current use may be a promising disease-modifying AD treatment. This hypothesis merits testing through adequately powered clinical trials in at-risk individuals during preclinical stages of disease progression.

Hydroxychloroquine is Metabolized by Cytochrome P450 2D6, 3A4, and 2C8, and Inhibits Cytochrome P450 2D6, while its Metabolites also Inhibit Cytochrome P450 3A in vitro

This study aimed to explore the cytochrome P450 (CYP) metabolic and inhibitory profile of hydroxychloroquine (HCQ). Hydroxychloroquine metabolism was studied using human liver microsomes (HLMs) and recombinant CYP enzymes. The inhibitory effects of HCQ and its metabolites on nine CYPs were also determined in HLMs, using an automated substrate cocktail method. Our metabolism data indicated that CYP3A4, CYP2D6, and CYP2C8 are the key enzymes involved in HCQ metabolism. All three CYPs formed the primary metabolites desethylchloroquine (DCQ) and desethylhydroxychloroquine (DHCQ) to various degrees. Although the intrinsic clearance (CL_int) value of HCQ depletion by recombinant CYP2D6 was > 10-fold higher than that by CYP3A4 (0.87 versus 0.075 µl/min/pmol), scaling of recombinant CYP CL_int to HLM level resulted in almost equal HLM CL_int values for CYP2D6 and CYP3A4 (11 and 14 µl/min/mg, respectively). The scaled HLM CL_int of CYP2C8 was 5.7 µl/min/mg. Data from HLM experiments with CYP-selective inhibitors also suggested relatively equal roles for CYP2D6 and CYP3A4 in HCQ metabolism, with a smaller contribution by CYP2C8. In CYP inhibition experiments, HCQ, DCQ, DHCQ, and the secondary metabolite didesethylchloroquine were direct CYP2D6 inhibitors, with 50% inhibitory concentration (IC₅₀) values between 18 and 135 µM. HCQ did not inhibit other CYPs. Furthermore, all metabolites were time-dependent CYP3A inhibitors (IC₅₀ shift 2.2-3.4). To conclude, HCQ is metabolized by CYP3A4, CYP2D6, and CYP2C8 in vitro. HCQ and its metabolites are reversible CYP2D6 inhibitors, and HCQ metabolites are time-dependent CYP3A inhibitors. These data can be used to improve physiologically-based pharmacokinetic models and update drug-drug interaction risk estimations for HCQ. SIGNIFICANCE STATEMENT: While CYP2D6, CYP3A4, and CYP2C8 have been shown to mediate chloroquine biotransformation, it appears that the role of CYP enzymes in hydroxychloroquine (HCQ) metabolism has not been studied. In addition, little is known about the CYP inhibitory effects of HCQ. Here, we demonstrate that CYP2D6, CYP3A4, and CYP2C8 are the key enzymes involved in HCQ metabolism. Furthermore, our findings show that HCQ and its metabolites are inhibitors of CYP2D6, which likely explains the previously observed interaction between HCQ and metoprolol.

Low-molecular weight inhibitors of the alternative complement pathway

Dysregulation of the alternative complement pathway predisposes individuals to a number of diseases. It can either be evoked by genetic alterations in or by stabilizing antibodies to important pathway components and typically leads to severe diseases such as paroxysmal nocturnal hemoglobinuria, atypical hemolytic uremic syndrome, C3 glomerulopathy, and age-related macular degeneration. In addition, the alternative pathway may also be involved in many other diseases where its amplifying function for all complement pathways might play a role. To identify specific alternative pathway inhibitors that qualify as therapeutics for these diseases, drug discovery efforts have focused on the two central proteases of the pathway, factor B and factor D. Although drug discovery has been challenging for a number of reasons, potent and selective low-molecular weight (LMW) oral inhibitors have now been discovered for both proteases and several molecules are in clinical development for multiple complement-mediated diseases. While the clinical development of these inhibitors initially focuses on diseases with systemic and/or peripheral tissue complement activation, the availability of LMW inhibitors may also open up the prospect of inhibiting complement in the central nervous system where its activation may also play an important role in several neurodegenerative diseases.

Biologic Functions of Hydroxychloroquine in Disease: From COVID-19 to Cancer

Chloroquine (CQ) and Hydroxychloroquine (HCQ), initially utilized in the treatment of malaria, have now developed a long list of applications. Despite their clinical relevance, their mechanisms of action are not clearly defined. Major pathways by which these agents are proposed to function include alkalinization of lysosomes and endosomes, downregulation of C-X-C chemokine receptor type 4 (CXCR4) expression, high-mobility group box 1 protein (HMGB1) inhibition, alteration of intracellular calcium, and prevention of thrombus formation. However, there is conflicting data present in the literature. This is likely the result of the complex overlapping pathways between these mechanisms of action that have not previously been highlighted. In fact, prior research has focused on very specific portions of particular pathways without describing these in the context of the extensive CQ/HCQ literature. This review summarizes the detailed data regarding CQ/HCQ's mechanisms of action while also providing insight into the overarching themes. Furthermore, this review provides clinical context to the application of these diverse drugs including their role in malaria, autoimmune disorders, cardiovascular disease, thrombus formation, malignancies, and viral infections.

Ivermectin role in COVID-19 treatment (IRICT): single-center, adaptive, randomized, double-blind, placebo-controlled, clinical trial

BACKGROUND

To investigate the efficacy and safety of ivermectin compared to hydroxychloroquine and placebo in hospitalized moderate to severe COVID-19 patients.

RESEARCH DESIGN AND METHODS

The study was an adaptive, randomized, double-blinded, controlled, single-center trial. The study was a series of 3-arm comparisons between two different investigational therapeutic agents (ivermectin and hydroxychloroquine) and a placebo. There was interim monitoring to allow early stopping for futility, efficacy, or safety.

RESULTS

Ivermectin decreased survival time from 29 to 18.3 days (HR, 9.8, 95%CI, 3.7-26.2), while it did not shorten the recovery time (HR, 1.02, 95%CI, 0.69-1.5). Subgroup analysis showed an association between ivermectin-related mortality and baseline oxygen saturation level. Moreover, stratified groups showed higher risk among patients on high flow O2. Hydroxychloroquine delayed recovery from 10.1 to 12.5 days (HR, 0.62, 95%CI, 0.4-0.95) and non-significantly decreased survival time from 29 to 26.8 days (HR, 1.47, 95%CI, 0.73-2.9). However, 3 months mortality rates were increased with hydroxychloroquine (RR, 2.05, 95%CI, 1.33-3.16). Neither ivermectin nor hydroxychloroquine increased adverse events and demonstrated safety profile compared to placebo.

CONCLUSIONS

The study recommends against using either ivermectin or hydroxychloroquine for treatment of COVID-19 in hospitalized patients with any degree of severity. Clinical trial registration: www.clinicaltrials.gov identifier is: NCT04746365.

Hydroxychloroquine and Risk of Long QT Syndrome in Rheumatoid Arthritis: A Veterans Cohort Study With Nineteen-Year Follow-up

OBJECTIVE

Recent evidence suggests that hydroxychloroquine use is not associated with higher 1-year risk of long QT syndrome (LQTS) in patients with rheumatoid arthritis (RA). Less is known about its long-term risk, the examination of which was the objective of this study.

METHODS

We conducted a propensity score-matched active-comparator safety study of hydroxychloroquine in 8,852 veterans (mean age 64 ± 12 years, 14% women, 28% Black) with newly diagnosed RA. A total of 4,426 patients started on hydroxychloroquine and 4,426 started on another nonbiologic disease-modifying antirheumatic drug (DMARD) and were balanced on 87 baseline characteristics. The primary outcome was LQTS during 19-year follow-up through December 31, 2019.

RESULTS

Incident LQTS occurred in 4 (0.09%) and 5 (0.11%) patients in the hydroxychloroquine and other DMARD groups, respectively, during the first 2 years. Respective 5-year incidences were 17 (0.38%) and 6 (0.14%), representing 11 additional LQTS events in the hydroxychloroquine group (number needed to harm 403; [95% confidence interval (95% CI)], 217-1,740) and a 181% greater relative risk (95% CI 11%-613%; P = 0.030). Although overall 10-year risk remained significant (hazard ratio 2.17; 95% CI 1.13-4.18), only 5 extra LQTS occurred in hydroxychloroquine group over the next 5 years (years 6-10) and 1 over the next 9 years (years 11-19). There was no association with arrhythmia-related hospitalization or all-cause mortality.

CONCLUSIONS

Hydroxychloroquine use had no association with LQTS during the first 2 years after initiation of therapy. There was a higher risk thereafter that became significant after 5 years of therapy. However, the 5-year absolute risk was very low, and the absolute risk difference was even lower. Both risks attenuated during longer follow-up. These findings provide evidence for long-term safety of hydroxychloroquine in patients with RA.

Impact of Liver Functions by Repurposed Drugs for COVID-19 Treatment

Liver injury is an important complication that may arise in patients suffering from coronavirus disease 2019 (COVID-19) and is accompanied by a transient increase of transaminases and/or other liver enzymes. Liver function test (LFT) abnormalities generally disappear when the COVID-19 resolves or hepatotoxic drugs are discontinued. The LFT abnormalities are associated with drug-induced liver injury (DILI), due to the overuse of antimalarials, antivirals, and antimicrobials. Studies have reported varying levels of these liver injuries in COVID-19 patients; however, most involve elevated serum aminotransferases. Hepatic dysfunction is significantly high in patients with severe illness and has poor outcome. Normally, the liver is involved in the metabolism of many drugs, including nucleoside analogs and protease inhibitors, which are currently repurposed to treat COVID-19. In addition to the manifestation of COVID-19, drugs implemented in its treatment may aggravate liver injuries. Thus, DILI should be considered especially in those COVID-19 patients with underlying liver disease. It was unclear whether the elevated liver enzymes have originated from the underlying disease or DILI in this population. Furthermore, it is difficult to establish a direct relationship between a specific drug and liver injury. Another possible effect of liver damage may due to inflammatory cytokine storm in severe COVID-19. Liver injury can change metabolism, excretion, dosing, and expected concentrations of the drugs, which may make it difficult to achieve a therapeutic dose of the drug or increase the risk of adverse effects. These repurposed drugs have shown limited efficacy against the virus and the disease itself; however, they still pose risk of adverse effects. Careful and close monitoring of LFTs in COVID-19 patients can provide early diagnosis of liver injury, and the risk of DILI could be reduced. Also, drug interactions in liver-transplanted patients should always be kept in mind for certain immunosuppressive therapies and their known signs of DILI. Altogether, abnormal LFTs should not be regarded as a contraindication to use COVID-19 experimental therapies if needed under emergent status.

Metformin: Is it a drug for all reasons and diseases?

Metformin was first used to treat type 2 diabetes in the late 1950s and in 2022 remains the first-choice drug used daily by approximately 150 million people. An accumulation of positive pre-clinical and clinical data has stimulated interest in re-purposing metformin to treat a variety of diseases including COVID-19. In polycystic ovary syndrome metformin improves insulin sensitivity. In type 1 diabetes metformin may help reduce the insulin dose. Meta-analysis and data from pre-clinical and clinical studies link metformin to a reduction in the incidence of cancer. Clinical trials, including MILES (Metformin In Longevity Study), and TAME (Targeting Aging with Metformin), have been designed to determine if metformin can offset aging and extend lifespan. Pre-clinical and clinical data suggest that metformin, via suppression of pro-inflammatory pathways, protection of mitochondria and vascular function, and direct actions on neuronal stem cells, may protect against neurodegenerative diseases. Metformin has also been studied for its anti-bacterial, -viral, -malaria efficacy. Collectively, these data raise the question: Is metformin a drug for all diseases? It remains unclear as to whether all of these putative beneficial effects are secondary to its actions as an anti-hyperglycemic and insulin-sensitizing drug, or result from other cellular actions, including inhibition of mTOR (mammalian target for rapamycin), or direct anti-viral actions. Clarification is also sought as to whether data from ex vivo studies based on the use of high concentrations of metformin can be translated into clinical benefits, or whether they reflect a 'Paracelsus' effect. The environmental impact of metformin, a drug with no known metabolites, is another emerging issue that has been linked to endocrine disruption in fish, and extensive use in T2D has also raised concerns over effects on human reproduction. The objectives for this review are to: 1) evaluate the putative mechanism(s) of action of metformin; 2) analyze the controversial evidence for metformin's effectiveness in the treatment of diseases other than type 2 diabetes; 3) assess the reproducibility of the data, and finally 4) reach an informed conclusion as to whether metformin is a drug for all diseases and reasons. We conclude that the primary clinical benefits of metformin result from its insulin-sensitizing and antihyperglycaemic effects that secondarily contribute to a reduced risk of a number of diseases and thereby enhancing healthspan. However, benefits like improving vascular endothelial function that are independent of effects on glucose homeostasis add to metformin's therapeutic actions.

Population Pharmacokinetics of Hydroxychloroquine Sulfate in Healthcare Workers, Given for Prophylaxis Against Coronavirus Disease 2019 (COVID-19) in India

Healthcare workers (HCWs) and frontline workers were recommended hydroxychloroquine (HCQ) 400 mg twice a day on day 1, followed by 400 mg once weekly for the next 7 weeks, as prophylaxis against COVID-19. There was limited information on the population pharmacokinetics (popPK) of HCQ in an Indian setting when administered for prophylaxis against COVID-19, and hence this study was proposed. It was a multicentric prospective study conducted at 3 sites in India wherein HCWs who were already on HCQ prophylaxis, who were about to start prophylaxis or who had stopped the prophylaxis for any reason were enrolled. Each participant gave 2 to 6 blood samples at different time points and whole-blood HCQ concentrations were assayed using liquid chromatography with tandem mass spectrometry (LC MS/MS). popPK analysis was performed using PUMAS 1.1.0. A total of N = 338 blood samples from N = 121 participants were included in the popPK analysis. A 2-compartment structural model with linear elimination was able to explain the observed data. Body weight was found to be a significant covariate influencing drug clearance. The final model was assessed using goodness-of-fit plots, a visual predictive check and a bootstrap, all of which confirmed that the model was appropriate. Simulations based on the current regimen showed that trough values were below the half-maximal effective concentration (EC50) of 0.7 μmol against COVID-19. A new weight-based dosage regimen was proposed to maintain the trough concentration above the EC50 threshold.

A Capillary Electrophoresis-Based Method for the Measurement of Hydroxychloroquine and Its Active Metabolite Desethyl Hydroxychloroquine in Whole Blood in Patients with Rheumatoid Arthritis

A capillary electrophoresis method was developed to detect and measure hydroxychloroquine (HCQ) and its active metabolite desethyl hydroxychloroquine (DHCQ) in whole blood in patients with rheumatoid arthritis. The best separation in terms of peak area reproducibility, migration time, peak shape, and resolution of adjacent peaks was obtained in a 60 cm, 75 µm i.d. uncoated fused-silica capillary using a background electrolyte mixture of an aqueous 55 mmol/L TRIS solution brought to pH 2.6 with phosphoric acid and methanol (85:15) and a voltage and a temperature of separation of 20 kV and 30 °C, respectively. Analytes were separated in less than 12 min, with excellent linearity (R² ≥ 0.999) in the concentration range of 0.5–8 µmol/L. The recovery of analytes spiked in whole blood was 99–101% for HCQ and 98–99% for DHCQ. Analysis of five samples from patients with rheumatoid arthritis receiving HCQ 400 mg daily yielded mean steady-state concentrations of 2.27 ± 1.61 and 1.54 ± 0.55 μmol/L for HCQ and DHCQ, respectively, with a HCQ to DHCQ ratio of 1.40 ± 0.77.

Hydroxychloroquine Blood Concentrations Can Be Clinically Relevant Also After Drug Discontinuation

BACKGROUND AND OBJECTIVE

Hydroxychloroquine was widely used during the severe acute respiratory syndrome coronavirus 2 pandemic as an antiviral drug. Most previous pharmacokinetic/pharmacodynamic studies on hydroxychloroquine were conducted on healthy volunteers or patients receiving long-term therapy. There are no studies on the elimination of hydroxychloroquine after short-term treatments. Hydroxychloroquine is known to have a pro-arrhythmic effect through QT interval prolongation, but data in this setting are not conclusive. Our aims were to estimate the time needed for hydroxychloroquine concentrations (CHCQ) to drop to a safe concentration (500 ng/mL) after a short-term therapeutic cycle and to correlate the corrected QT interval with CHCQ.

METHODS

We collected blood samples and electrocardiograms of patients who underwent short-term therapy with hydroxychloroquine during drug intake and after discontinuation. Hydroxychloroquine concentrations were determined by high-performance liquid chromatography-tandem mass spectrometry and analysed with a linear regression model to estimate the elimination time of the drug after its discontinuation. We conducted a multivariate analysis of the corrected QT interval correlation with CHCQ.

RESULTS

Our data suggest that short-term hydroxychloroquine courses can generate significant CHCQ persisting above 500 ng/mL up to 16 days after discontinuation of treatment. Corrected QT interval prolongation significantly correlates with CHCQ.

CONCLUSIONS

The study confirms the long half-life of hydroxychloroquine and its effect on the corrected QT interval even after short-term courses of the drug. This can inform the clinician using hydroxychloroquine treatments that it would be safer to start or re-initiate treatments with corrected QT interval-prolonging potential 16 days after hydroxychloroquine discontinuation.

Impact of an Electronic Decision Support Tool to Improve Ophthalmic Safety in Hydroxychloroquine Prescribing Practices

BACKGROUND AND OBJECTIVE

The purpose of this study was to implement a clinical decision support tool (CDS) and assess its impact on adherence to 2016 American Academy of Ophthalmology (AAO) hydroxychloroquine dosing recommendations.

PATIENTS AND METHODS

This retrospective, interventional study implemented an automated alert to calculate maximum daily hydroxychloroquine dose based on 2016 AAO recommendations and flag noncompliant orders. Prevalence of excessive dosing after CDS implementation was assessed.

RESULTS

A total of 7,417 patients met inclusion criteria. After intervention, prevalence of excessive dosing decreased from 27.4% to 21.1% (P < .001) among all prescriptions and from 26.8% to 16.2% (P < .001) among new prescriptions. Daily doses exceeding 400 mg decreased from 0.8% to 0.02% (P < .001). Risk factors for excessive dosing included low weight (odds ratio, 75.6 [95% CI, 54.0 to 105.8]) and nonrheumatologist prescriber (odds ratio, 1.60 to 3.63; all P < .005).

CONCLUSIONS

This study highlights the efficacy of a CDS in reducing excessive hydroxychloroquine dosing and improving adherence to AAO ophthalmic safety guidelines. [Ophthalmic Surg Lasers Imaging 2022;53:310-316.].

Physiologically-Based Pharmacokinetics Modeling for Hydroxychloroquine as a Treatment for Malaria and Optimized Dosing Regimens for Different Populations

Malaria is a severe parasite infectious disease with high fatality. As one of the approved treatments of this disease, hydroxychloroquine (HCQ) lacks clinical administration guidelines for patients with special health conditions and co-morbidities. This may result in improper dosing for different populations and lead them to suffer from severe side effects. One of the most important toxicities of HCQ overdose is cardiotoxicity. In this study, we built and validated a physiologically based pharmacokinetic modeling (PBPK) model for HCQ. With the full-PBPK model, we predicted the pharmacokinetic (PK) profile for malaria patients without other co-morbidities under the HCQ dosing regimen suggested by Food and Drug Administration (FDA) guidance. The PK profiles for different special populations were also predicted and compared to the normal population. Moreover, we proposed a series of adjusted dosing regimens for different populations with special health conditions and predicted the concentration-time (C-T) curve of the drug plasma concentration in these populations which include the pregnant population, elderly population, RA patients, and renal impairment populations. The recommended special population-dependent dosage regimens can maintain the similar drug levels observed in the virtual healthy population under the original dosing regimen provided by FDA. Last, we developed mathematic formulas for predicting dosage based on a patient’s body measurements and two indexes of renal function (glomerular filtration rate and serum creatine level) for the pediatric and morbidly obese populations. Those formulas can facilitate personalized treatment of this disease. We hope to provide some advice to clinical practice when taking HCQ as a treatment for malaria patients with special health conditions or co-morbidities so that they will not suffer from severe side effects due to higher drug plasma concentration, especially cardiotoxicity.

Changes in Sewage Sludge Chemical Signatures During a COVID-19 Community Lockdown, Part 1: Traffic, Drugs, Mental Health, and Disinfectants

The early months of the COVID-19 pandemic and the associated shutdowns disrupted many aspects of daily life and thus caused changes in the use and disposal of many types of chemicals. While records of sales, prescriptions, drug overdoses, and so forth provide data about specific chemical uses during this time, wastewater and sewage sludge analysis can provide a more comprehensive overview of chemical changes within a region. We analyzed primary sludge from a wastewater-treatment plant in Connecticut, USA, collected March 19 to June 30, 2020. This time period encompassed the first wave of the pandemic, the initial statewide stay at home order, and the first phase of reopening. We used liquid chromatography-high-resolution mass spectrometry and targeted and suspect screening strategies to identify 78 chemicals of interest, which included pharmaceuticals, illicit drugs, disinfectants, ultraviolet (UV) filters, and others. We analyzed trends over time for the identified chemicals using linear trend analyses and multivariate comparisons (p < 0.05). We found trends related directly to the pandemic (e.g., hydroxychloroquine, a drug publicized for its potential to treat COVID-19, had elevated concentrations in the week following the implementation of the US Emergency Use Authorization), as well as evidence for seasonal changes in chemical use (e.g., increases for three UV-filter compounds). Though wastewater surveillance during the pandemic has largely focused on measuring severe acute respiratory syndrome-coronavirus-2 RNA concentrations, chemical analysis can also show trends that are important for revealing the public and environmental health effects of the pandemic. Environ Toxicol Chem 2022;41:1179-1192. © 2021 SETAC.

The relationship between hydroxychloroquine plasma concentration and COVID-19 outcomes in rheumatoid arthritis patients in Saudi Arabia

Background

The drug hydroxychloroquine (HCQ) is widely used to treat rheumatoid arthritis (RA) and has been repurposed for the treatment of COVID-19. This study aims to determine whether HCQ concentration levels in individuals with RA alter the incidence of COVID-19 or its complications.

Methods

We collected plasma samples from 13 individuals with confirmed rheumatoid arthritis (RA) to measure HCQ concentration levels. The study included individuals at least 18 years old who had been taking HCQ for at least six months at daily doses ranging from 200 to 400 mg.

Results

The study enrolled a total of 13 RA patients. All patients were chronic HCQ users. Among the 13 patients, 7 patients were receiving HCQ at a dose of 200 mg per day, and 6 patients were receiving HCQ at a dose of 400 mg per day. COVID-19 confirmed cases accounted for approximately 46% of all patients. Half of the infected patients (n = 3) were taking a daily dose of 200 mg daily, while the other half were taking 400 mg daily. COVID-19 symptoms ranged from mild to moderate, and the intensity of the symptoms was not severe enough to necessitate hospitalization. COVID-19 symptoms in RA patients included headache, fever, fatigue, dry cough, and loss of taste or smell.

Conclusions

Our findings indicated that there was no correlation between HCQ concentrations in rheumatoid arthritis patients and the occurrence of COVID-19 or its complications.

Changes in Sewage Sludge Chemical Signatures During a COVID-19 Community Lockdown, Part 1: Traffic, Drugs, Mental Health, and Disinfectants

The early months of the COVID-19 pandemic and the associated shutdowns disrupted many aspects of daily life and thus caused changes in the use and disposal of many types of chemicals. While records of sales, prescriptions, drug overdoses, and so forth provide data about specific chemical uses during this time, wastewater and sewage sludge analysis can provide a more comprehensive overview of chemical changes within a region. We analyzed primary sludge from a wastewater-treatment plant in Connecticut, USA, collected March 19 to June 30, 2020. This time period encompassed the first wave of the pandemic, the initial statewide stay at home order, and the first phase of reopening. We used liquid chromatography-high-resolution mass spectrometry and targeted and suspect screening strategies to identify 78 chemicals of interest, which included pharmaceuticals, illicit drugs, disinfectants, ultraviolet (UV) filters, and others. We analyzed trends over time for the identified chemicals using linear trend analyses and multivariate comparisons (p < 0.05). We found trends related directly to the pandemic (e.g., hydroxychloroquine, a drug publicized for its potential to treat COVID-19, had elevated concentrations in the week following the implementation of the US Emergency Use Authorization), as well as evidence for seasonal changes in chemical use (e.g., increases for three UV-filter compounds). Though wastewater surveillance during the pandemic has largely focused on measuring severe acute respiratory syndrome-coronavirus-2 RNA concentrations, chemical analysis can also show trends that are important for revealing the public and environmental health effects of the pandemic. Environ Toxicol Chem 2022;41:1179-1192. © 2021 SETAC.

Prevalence of ECG testing and characteristics among new hydroxychloroquine and chloroquine users within a multi-center tertiary care center

COVID-19 raised concern regarding cardiotoxicity and QTc prolongation of hydroxychloroquine (HCQ) and chloroquine (CQ). We examined the frequency and patient factors associated with ECG testing and the detection of prolonged QTc among new HCQ/CQ users in a large academic medical system. 10,248 subjects with a first HCQ/CQ prescription (1/2015–3/2020) were included. We assessed baseline (1 year prior to and including day of initiation of HCQ/CQ through 2 months after initial HCQ/CQ prescription) and follow-up (10 months after the baseline period) patient characteristics and ECGs obtained from electronic health records. Among 8384 female HCQ/CQ new users, ECGs were obtained for 22.3%, 14.3%, and 7.6%, at baseline, follow, and both periods, respectively. Among 1864 male HCQ/CQ new users, ECGs were obtained more frequently at baseline (29.7%), follow-up (18.0%), and both periods (11.3%). Female HCQ/CQ users with a normal QTc at baseline but prolonged QTc (> 470 ms) at follow-up (13.1%) were older at HCQ/CQ initiation [mean 64.7 (SD 16.5) vs. 58.7 (SD 16.9) years, p = 0.004] and more likely to have history of myocardial infarction (41.0% vs. 21.6%, p = 0.0003) compared to those who had normal baseline and follow-up QTc. The frequency of prolonged QTc development was similar (12.4%) among male HCQ/CQ new users (> 450 ms). Prior to COVID-19, ECG testing before and after HCQ/CQ prescription was infrequent, particularly for females who are disproportionately affected by rheumatic diseases and were just as likely to develop prolonged QTc (> 1/10 new users). Prospective studies are needed to guide future management of HCQ/CQ therapy in rheumatic populations.

Population Pharmacokinetics of Hydroxychloroquine and 3 Metabolites in COVID-19 Patients and Pharmacokinetic/Pharmacodynamic Application

We develop a population pharmacokinetic model for hydroxychloroquine (HCQ) and three of its metabolites (desethylhydroxychloroquine, Des HCQ; desethylchloroquine, DesCQ; and didesethylchloroquine, didesCQ) in COVID-19 patients in order to determine whether a pharmacokinetic (PK)/pharmacodynamic (PD) relationship was present. The population PK of HCQ was described using non-linear mixed effects modelling. The duration of hospitalization, the number of deaths, and poor clinical outcomes (death, transfer to ICU, or hospitalization ≥ 10 d) were evaluated as PD parameters. From 100 hospitalized patients (age = 60.7 ± 16 y), 333 BHCQ and M were available for analysis. The data for BHCQ were best described by a four-compartment model with a first-order input (KA) and a first-order output. For M, the better model of the data used one compartment for each metabolite with a first-order input from HCQ and a first-order output. The fraction of HCQ converted to the metabolites was 75%. A significant relationship was observed between the duration of hospitalization and BHCQ at 48 h (r² = 0.12; p = 0.0052) or 72 h (r² = 0.16; p = 0.0012). At 48 h or 72 h, 87% or 91% of patients vs. 63% or 62% had a duration < 25 d with a BHCQ higher or below 200 μg/L, respectively. Clinical outcome was significantly related to BHCQ at 48 h (good outcome 369 +/- 181 μg/L vs. poor 285 +/- 144 μg/L; p = 0.0441) but not at 72 h (407 +/- 207 μg/L vs. 311 +/- 174 μg/L; p = 0.0502). The number of deaths was not significantly different according to the trough concentration (p = 0.972 and 0.836 for 48 h and 72 h, respectively).

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.

Pulmonary Delivery of Aerosolized Chloroquine and Hydroxychloroquine to Treat COVID-19: In Vitro Experimentation to Human Dosing Predictions

In vitro screening for pharmacological activity of existing drugs showed chloroquine and hydroxychloroquine to be effective against severe acute respiratory syndrome coronavirus 2. Oral administration of these compounds to obtain desired pulmonary exposures resulted in dose-limiting systemic toxicity in humans. However, pulmonary drug delivery enables direct and rapid administration to obtain higher local tissue concentrations in target tissue. In this work, inhalable formulations for thermal aerosolization of chloroquine and hydroxychloroquine were developed, and their physicochemical properties were characterized. Thermal aerosolization of 40 mg/mL chloroquine and 100 mg/mL hydroxychloroquine formulations delivered respirable aerosol particle sizes with 0.15 and 0.33 mg per 55 mL puff, respectively. In vitro toxicity was evaluated by exposing primary human bronchial epithelial cells to aerosol generated from Vitrocell. An in vitro exposure to 7.24 μg of chloroquine or 7.99 μg hydroxychloroquine showed no significant changes in cilia beating, transepithelial electrical resistance, and cell viability. The pharmacokinetics of inhaled aerosols was predicted by developing a physiologically based pharmacokinetic model that included a detailed species-specific respiratory tract physiology and lysosomal trapping. Based on the model predictions, inhaling emitted doses comprising 1.5 mg of chloroquine or 3.3 mg hydroxychloroquine three times a day may yield therapeutically effective concentrations in the lung. Inhalation of higher doses further increased effective concentrations in the lung while maintaining lower systemic concentrations. Given the theoretically favorable risk/benefit ratio, the clinical significance for pulmonary delivery of aerosolized chloroquine and hydroxychloroquine to treat COVID-19 needs to be established in rigorous safety and efficacy studies. Graphical abstract.

QTc-interval prolongation and increased risk of sudden cardiac death associated with hydroxychloroquine

AIMS:

Hydroxychloroquine and chloroquine ([hydroxy]chloroquine) are drugs used to treat malaria and rheumatological disorders and were recently suggested as beneficial for prevention and treatment of patients with coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 infection. However, longitudinal studies to assess the electrocardiographic and cardiotoxic effects of these drugs are limited. In this study, we aimed to investigate the effect of these drugs on QTc-interval and incidence of sudden cardiac death (SCD).

METHODS

We designed a longitudinal follow-up study of individuals within the prospective population-based Rotterdam Study. Eligible individuals had available data on medication and repeated ECG measurements. The study period was between 1 January 1991 and 1 January 2014. We studied on current and past use of [hydroxy]chloroquine as a time-varying exposure; high versus low daily dose of [hydroxy]chloroquine. QTc-interval duration, and the occurrence of SCD were the main outcomes. SCD was defined as an unexpected and sudden death due to cardiac arrhythmia within one hour of the onset of acute symptoms, and in patients without cardiac symptoms within 24 hours before death.

RESULTS

Among the study population of 14 594 individuals (58.8% women) with an average age of 65 years, 346 patients used [hydroxy]chloroquine at any time during follow-up. The total number of SCD cases was 609. In a multiple linear mixed model analysis, the current use of [hydroxy]chloroquine was associated with a significantly increased duration of the QTc-interval of 8.1 ms (95% CI: 3.6; 12.6) compared with non-users. The association was stronger among current-high daily dosage [15.3 (95%CI: 7.0; 23.6)] compared with current-low daily dosage [5.5 (95%CI: 0.4; 10.7)] users. In a Cox proportional hazard regression analysis, the risk of SCD was significantly higher in participants who were current users of [hydroxy]chloroquine than in non-users [adjusted hazard ratio; 3.7 (95%CI: 1.1; 12.6)].

CONCLUSIONS

In this longitudinal study, persons who received [hydroxy]chloroquine had an increased QTc-interval duration and the association was dose-dependent. [Hydroxy]chloroquine was associated with a significantly increased risk of SCD. As long as their activity against COVID-19 is controversial, cardiotoxicity is a strong argument against using these drugs to treat COVID-19 infections.

Seven day continuous ambulatory electrocardiographic telemetric study with pocket electrocardiographic recording device for detecting hydroxychloroquine induced arrhythmias

Objective:

The use of hydroxychloroquine (HCQ) for COVID-19 treatment and prophylaxis raised issues concerning its cardiac safety owing to the possibility of QT prolongation and arrhythmias. There was no study on long-term electrocardiographic telemetry monitoring of patients taking HCQ. We planned a continuous electrocardiographic Holter telemetry of these patients for 7 days.

Material and Methods:

Health care workers taking HCQ as pre exposure prophylaxis and patients on HCQ were monitored using seven day Holter electrocardiographic telemetry with continuous beat to beat analysis. Telemetry can instantly convey any arrhythmic event or significant QT prolongation to the medical faculty.

Results:

Twenty-five participants with a mean age of 42.4 ± 14.1 years were included in the study; 40% were females. Twenty percent of participants needed to stop HCQ. Four patients developed QT prolongation >500 ms and needed to stop HCQ, one patient had accelerated idioventricular rhythm and stopped treatment, and one had short episodes of atrial fibrillation. No malignant arrhythmia or ventricular arrhythmia, or torsade de pointis were noted. No episode of significant conduction disturbance and arrhythmic death was noted. Baseline mean QTc was 423.96 ± 32.18 ms, mean QTc corrected at 24 h was 438.93 ± 37.95, mean QTc was 451.879 ± 37.99 at 48 h, and change in baseline mean QTc to max QTc was 30.74 ± 21.75 ms at 48 h. All those who developed QTc prolongation >500 ms were greater than 50 years of age.

Conclusion:

Ambulatory telemetry ECG monitoring detects early QT prolongation, and stopping drugs prevents malignant arrhythmias. HCQ seems to have less risk of QT prolongation in young, healthy individuals.

Removal of hydroxychloroquine from an aqueous solution using living microalgae: Effect of operating parameters on removal efficiency and mechanisms

Wastewater contaminated with hydroxychloroquine (HCQ) poses a serious threat to the environment and human life. This study aimed to evaluate the ability of living microalgae to remove HCQ from an aqueous solution. Batch mode experiments were conducted under different conditions to investigate the effect of operating parameters on HCQ removal efficiency and mechanisms. Equilibrium, kinetic and thermodynamic study was also carried out to better describe the interactions between HCQ and microalgae. The maximum HCQ removal was 92.10 ± 1.25% obtained under optimal pH of 9.9 ± 0.1, a contact time of 45 min, a stirring speed of 300 rpm, an initial HCQ concentration of 20 mg/L, and a microalgae dose of 100 mg/L. The Langmuir isotherm and the pseudo-second-order kinetic model were best suited for the biosorption experiments, and the maximum biosorption capacity was 339.02 mg/g. The thermodynamic study showed that the biosorption process was exothermic and spontaneous. Experiments on real wastewater showed that the HCQ removal was not significantly affected by the presence of other contaminants in the water. PRACTITIONER POINTS: The best HCQ removal was 92.10 ± 1.25% obtained under optimal conditions. The Langmuir isotherm and the pseudo-second-order kinetic model were best suited for the biosorption experiments. The maximum biosorption capacity was 339.02 mg/g. The thermodynamic study showed that the biosorption process was exothermic and spontaneous. The microalgae studied can be successfully used in HCQ removal from water.

Knowledge and compliance of hydroxychloroquine prophylaxis for severe acute respiratory syndrome coronavirus 2 infection among Indian health-care workers

Objective:

In the initial days of the coronavirus disease 2019 (COVID-19) pandemic, the Indian Council of Medical Research (ICMR) recommended the use of hydroxychloroquine (HCQ) as chemoprophylaxis for health-care workers (HCWs) involved in the care of COVID-19 patients. The present survey aimed to assess the knowledge and compliance of HCQ prophylaxis as per the ICMR recommendations among Indian HCWs during the first wave of the pandemic.

Methods:

A validated 19-item questionnaire-based survey was distributed to HCWs in our apex tertiary care institute who had completed their duties in the COVID-19 wards to assess the knowledge, attitude, and compliance of all sections of HCWs regarding the ICMR-recommended HCQ prophylaxis. Participation in the survey was voluntary, and anonymity was maintained. Data obtained from the responses were collated and analyzed.

Findings:

Two hundred and fourteen out of 250 HCWs completed the survey (85.6% response rate). Among 214 participants, 87.9% were below the age of 40 years. 83.2% were aware of the use of HCQ for possible prevention of COVID-19 infection, while only 24.6% took HCQ for 7 weeks as was recommended during that period. The main reasons given by 37.3% of the HCWs for not taking HCQ were their knowledge and research on HCQ, where side effects were prominent. Side effects were reported by 35% of the respondents, of which the most notable was nausea/vomiting (14%) followed by gastritis (12%).

Conclusion:

The poor compliance with HCQ prophylaxis by HCWs was influenced by their knowledge and research, lack of strong scientific evidence, and drug-associated adverse effects.

A review on epidemiology, genomic characteristics, spread, and treatments of COVID-19

In December 2019, a new form of coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) started spreading in Wuhan, China. According to the situation report-95 published by the World Health Organization (WHO), the coronavirus disease spread rapidly to 213 countries and territories by April 24, 2020, with the number of confirmed cases and deaths of 26,26,321 and 1,81,938, respectively. The WHO declared coronavirus disease 2019 (COVID-19) as a pandemic on March 11, 2020. People living in many countries are in lockdown and staying at home because of this deadly virus. Patients of COVID-19 are reported to have single or multiple symptoms, while some patients do not have any remarkable symptom at all. Patients have reported symptoms of dry cough, sore throat, fever, fatigue, breathing problem, and gastrointestinal infection. COVID-19 may become very dangerous especially for aged people and people with any other disease such as diabetes, kidney problem, etc. In that case, the virus can cause acute respiratory distress syndrome and cytokine storm. The whole world is in lockdown because of this deadly virus. Currently, there is no particular cure for this disease; however, researchers are trying to find appropriate antiviral and repurposed drugs. This chapter provides a review on the different aspects of COVID-19 including the epidemiology, genomic sequence, and clinical characteristics; current medical treatment options; and development of vaccines and drugs.

Myth surrounding the FDA disapproval of hydroxychloroquine sulfate and chloroquine phosphate as drugs for coronavirus disease 2019

Chloroquine (CQ) and its analog hydroxychloroquine (HCQ) are popular antimalarial drugs that also exhibit wide range of activities against other diseases such as cancer, diabetes, HIV, and microbial infections, among others. They are also reported to possess antioxidant properties. The popularity of these drugs skyrocketed with the emergence of coronavirus disease 2019 (COVID-19) that has caused the deaths of over 600,000,000 people worldwide just within 7 months. Due to the urgency of the time in discovering or repurposing new drugs that will be active against SARS-CoV-2, the causative agent of COVID-19, some initial in vitro studies found prospects in CQ and HCQ against SARS-CoV-2. HCQ instantly became a drug of choice over CQ for the treatment of COVID-19 patients because it is readily absorbed and less toxic. However, clinical studies found no positive indices to support the continued use of HCQ. This chapter looks into this by consulting current literatures in order to unravel the myth surrounding the approval and disapproval of the use of HCQ.

Targeted Delivery of Chloroquine to Antigen-Presenting Cells Enhances Inhibition of the Type I Interferon Response

Systemic lupus erythematosus (SLE) causes damaging inflammation in multiple organs via the accumulation of immune complexes. These complexes activate plasmacytoid dendritic cells (pDCs) via toll-like receptors (TLRs), contributing to disease pathogenesis by driving the secretion of inflammatory type I interferons (IFNs). Antimalarial drugs, such as chloroquine (CQ), are TLR antagonists used to alleviate inflammation in SLE. However, they require ∼3 months of continuous use before achieving therapeutic efficacy and can accumulate in the retinal pigment epithelium with chronic use, resulting in retinopathy. We hypothesized that poly(ethylene glycol)-b-poly(propylene sulfide) filamentous nanocarriers, filomicelles (FMs), could directly deliver CQ to pDCs via passive, morphology-based targeting to concentrate drug delivery to specific immune cells, improve drug activity by increased inhibition of type I IFN, and enhance efficacy per dose. Healthy human peripheral blood mononuclear cells were treated with soluble CQ or CQ-loaded FMs, stimulated with TLR agonists or SLE patient sera, and type I IFN secretion was quantified via multi-subtype IFN-α ELISA and MX1 gene expression using real-time reverse transcription-quantitative polymerase chain reaction. Our results showed that 50 μg CQ/mg FM decreased MX1 expression and IFN-α production after TLR activation with either synthetic nucleic acid agonists or immune complex-rich sera from SLE patients. Cellular uptake and biodistribution studies showed that FMs preferentially accumulate in human pDCs and monocytes in vitro and in tissues frequently damaged in SLE patients (i.e., kidneys), while sparing the eye in vivo. These results showed that nanocarrier morphology enables drug delivery, and CQ-FMs may be equally effective and more targeted than soluble CQ at inhibiting SLE-relevant pathways.

American College of Rheumatology White Paper on Antimalarial Cardiac Toxicity

Hydroxychloroquine (HCQ) and chloroquine (CQ) are well-established medications used in treating systemic lupus erythematosus and rheumatoid arthritis, as well as skin conditions such as cutaneous lupus erythematosus. In rare cases, arrhythmias and conduction system abnormalities, as well as cardiomyopathy, have been reported in association with HCQ/CQ use. Recently, however, the corrected QT interval (QTc)-prolonging potential of these medications, and risk of torsade de pointes (TdP) in particular, have been highlighted in the setting of their experimental use for COVID-19 infection. This report was undertaken to summarize the current understanding of HCQ/CQ cardiac toxicity, describe QTc prolongation and TdP risks, and discuss areas of priority for future research. A working group of experts across rheumatology, cardiology, and dermatology performed a nonsystematic literature review and offered a consensus-based expert opinion. Current data clearly indicate that HCQ and CQ are invaluable medications in the management of rheumatic and dermatologic diseases, but they are associated with QTc prolongation by directly affecting cardiac repolarization. Prescribing clinicians should be cognizant of this small effect, especially in patients taking additional medications that prolong the QTc interval. Long-term use of HCQ/CQ may lead to a cardiomyopathy associated with arrhythmias and heart failure. Risk and benefit assessment should be considered prior to initiation of any medication, and both initial and ongoing risk-benefit assessments are important with regard to prescription of HCQ/CQ. While cardiac toxicity related to HCQ/CQ treatment of rheumatic diseases is rarely reported, it can be fatal. Awareness of the potential adverse cardiac effects of HCQ and CQ can increase the safe use of these medications. There is a clear need for additional research to allow better understanding of the cardiovascular risk and safety profile of these therapies used in the management of rheumatic and cutaneous diseases.

Nebulised Isotonic Hydroxychloroquine Aerosols for Potential Treatment of COVID-19

The coronavirus disease 2019 (COVID-19) is an unprecedented pandemic that has severely impacted global public health and the economy. Hydroxychloroquine administered orally to COVID-19 patients was ineffective, but its antiviral and anti-inflammatory actions were observed in vitro. The lack of efficacy in vivo could be due to the inefficiency of the oral route in attaining high drug concentration in the lungs. Delivering hydroxychloroquine by inhalation may be a promising alternative for direct targeting with minimal systemic exposure. This paper reports on the characterisation of isotonic, pH-neutral hydroxychloroquine sulphate (HCQS) solutions for nebulisation for COVID-19. They can be prepared, sterilised, and nebulised for testing as an investigational new drug for treating this infection. The 20, 50, and 100 mg/mL HCQS solutions were stable for at least 15 days without refrigeration when stored in darkness. They were atomised from Aerogen Solo Ultra vibrating mesh nebulisers (1 mL of each of the three concentrations and, in addition, 1.5 mL of 100 mg/mL) to form droplets having a median volumetric diameter of 4.3-5.2 µm, with about 50-60% of the aerosol by volume < 5 µm. The aerosol droplet size decreased (from 4.95 to 4.34 µm) with increasing drug concentration (from 20 to 100 mg/mL). As the drug concentration and liquid volume increased, the nebulisation duration increased from 3 to 11 min. The emitted doses ranged from 9.1 to 75.9 mg, depending on the concentration and volume nebulised. The HCQS solutions appear suitable for preclinical and clinical studies for potential COVID-19 treatment.

Cardiovascular Safety of Hydroxychloroquine in US Veterans With Rheumatoid Arthritis

OBJECTIVE

Hydroxychloroquine (HCQ) may prolong the QT interval, a risk factor for torsade de pointes, a potentially fatal ventricular arrhythmia. This study was undertaken to examine the cardiovascular safety of HCQ in patients with rheumatoid arthritis (RA).

METHODS

We conducted an active comparator safety study of HCQ in a propensity score-matched cohort of 8,852 US veterans newly diagnosed as having RA between October 1, 2001 and December 31, 2017. Patients were started on HCQ (n = 4,426) or another nonbiologic disease-modifying antirheumatic drug (DMARD; n = 4,426) after RA diagnosis, up to December 31, 2018, and followed up for 12 months after therapy initiation, up to December 31, 2019.

RESULTS

Patients had a mean ± SD age of 64 ± 12 years, 14% were women, and 28% were African American. The treatment groups were balanced with regard to 87 baseline characteristics. There were 3 long QT syndrome events (0.03%), 2 of which occurred in patients receiving HCQ. Of the 56 arrhythmia-related hospitalizations (0.63%), 30 occurred in patients in the HCQ group (hazard ratio [HR] associated with HCQ 1.16 [95% confidence interval (95% CI) 0.68-1.95]). All-cause mortality occurred in 144 (3.25%) and 136 (3.07%) of the patients in the HCQ and non-HCQ groups, respectively (HR associated with HCQ 1.06 [95% CI, 0.84-1.34]). During the first 30 days of follow-up, there were no long QT syndrome events, 2 arrhythmia-related hospitalizations (none in the HCQ group), and 13 deaths (6 in the HCQ group).

CONCLUSION

Our findings indicate that the incidence of long QT syndrome and arrhythmia-related hospitalization is low in patients with RA during the first year after the initiation of HCQ or another nonbiologic DMARD. We found no evidence that HCQ therapy is associated with a higher risk of adverse cardiovascular events or death.

A critical review on environmental presence of pharmaceutical drugs tested for the covid-19 treatment

On March 11, 2020, the World Health Organization (WHO) declared COVID-19 a pandemic. The outbreak caused a worldwide impact, becoming a health threat to the general population and its professionals. To date, there are no specific antiviral treatments or vaccines for the COVID-19 infection, however, some drugs are being clinically tested. The use of these drugs on large scale raises great concern about their imminent environmental risk, since the elimination of these compounds by feces and urine associated with the inefficiency of sewage treatment plants in their removal can result in their persistence in the environment, putting in risk the health of humans and of other species. Thus, the goal of this work was to conduct a review of other studies that evaluated the presence of the drugs chloroquine, hydroxychloroquine, azithromycin, ivermectin, dexamethasone, remdesivir, favipiravir and some HIV antivirals in the environment. The research indicated the presence of these drugs in the environment in different regions, with concentration data that could serve as a basis for further comparative studies following the pandemic.

Effect of Pantoprazole on the Absorption of Hydroxychloroquinea A Randomized Drug-Drug Interaction Trial in Healthy Adults

Hydroxychloroquine as a weak basic compound with two amines is strongly enriched in cell compartments with low pH, suggesting that modification of gastric pH by coadministered proton pump inhibitors might reduce its solubility and absorption and thus its efficacy in patients. We addressed this question in a single-center, open-label, randomized, parallel drug-drug interaction trial in healthy adults (EudraCT No. 2020-001470-30). All participants received a single oral dose of 400-mg hydroxychloroquine, and one group additionally received 40 mg of pantoprazole once daily for 9 days dosed to steady state. Whole-blood samples were collected for 72 hours, and hydroxychloroquine was quantified by liquid chromatography-tandem mass spectrometry. Primary endpoints were whole-blood hydroxychloroquine areas under the concentration-time curve from 0 to 72 hours (AUC_0-72h ) and peak concentrations (C_max ). Unpaired 2-sided t-tests of the log transformed pharmacokinetic parameters were performed to compare both groups. Twenty-four participants (12 per group) were included. Hydroxychloroquine AUC_0-72h and C_max did not differ between groups without and with pantoprazole (arithmetic mean; AUC_0-72h , 7649 ng/ml • h, and 8429 ng/ml • h, P = .50; C_max , 448 ng/mL and 451.5 ng/mL, P = .96, respectively). Pantoprazole did not alter hydroxychloroquine absorption, indicating that proton pump inhibitors do not affect its bioavailability.

What the dental practitioner needs to know about pharmaco-therapeutic modalities of COVID-19 treatment: A review

BACKGROUND/PURPOSE

Several pharmacotherapeutic methods have been used for the treatment of COVID-19 with varying degrees of success. No definitive treatment or vaccine has been officially approved to-date. This review aimed to highlight COVID-19 pharmacotherapeutic agents that are relevant to dental practice in terms of their clinical indications in COVID-19 and dental practice, as well as their adverse effects as they impact the dental patient.

MATERIAL AND METHODS

Systematic search was performed using the following keywords combinations: Pharmacotherapy AND COVID-19 OR Pharmacotherapy AND SARS-CoV-2 OR Treatment AND COVID-19. Studies were categorized according to the type of pharmacotherapy used. Pharmacotherapeutic agents were extracted and only those relevant to dental practice were included for review.

RESULTS

For analysis, a total of 79 clinical trials research articles were included that included COVID-19 pharmacotherapeutic agents relevant to dental practice. Those were analgesics (paracetamol; non-steroidal anti-inflammatory agents); antibiotics (azithromycin, doxycycline, metronidazole); antivirals (penciclovir); and immunomodulatory agents (hydroxychloroquine, corticosteroids). While some COVID-19 drugs are less relevant to dental practice, as antivirals and hydroxychloroquine, their association with long-term adverse effects requires adequate knowledge among dental practitioners.

CONCLUSION

Many of COVID-19 pharmacotherapeutic agents are used to treat oral diseases particularly orofacial pain and inflammatory conditions. Furthermore, some of these drugs may induce adverse effects that complicate dental treatment. Thorough knowledge of COVID-19 therapy and its dental implications is essential for dental practitioners, and is expected to contribute to a better understanding and effective utilization of these therapeutic agents.

Comprehensive Cardiotoxicity Assessment of COVID-19 Treatments Using Human Induced Pluripotent Stem Cell-derived Cardiomyocytes

Coronavirus disease 2019 (COVID-19) continues to spread across the globe, with numerous clinical trials underway seeking to develop and test effective COVID-19 therapies, including remdesivir. Several ongoing studies have reported hydroxychloroquine-induced cardiotoxicity, including development of torsade de pointes (TdP). Meanwhile, human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are expected to serve as a tool for assessing drug-induced cardiotoxicity, such as TdP and contraction impairment. However, the cardiotoxicity of COVID-19 treatments has not been fully assessed using hiPSC-CMs. In the present study, we focused on drug repurposing with various modes of actions and examined the TdP risk associated with COVID-19 treatments using field potential using multi-electrode array (MEA) system and motion analysis with hiPSC-CMs. Hydroxychloroquine induced early after depolarization, while remdesivir, favipiravir, camostat and ivermectin had little effect on field potentials. We then analyzed electromechanical window (EMw), which is defined as the difference between field potential and contraction-relaxation durations. Hydroxychloroquine decreased EMw of hiPSC-CMs in a concentration-dependent manner. In contrast, other drugs have little effect. Our data suggest that hydroxychloroquine has proarrhythmic risk and other drugs have low proarrhythmic risk. Thus, hiPSC-CMs represent a useful tool for assessing the comprehensive cardiotoxicity caused by COVID-19 treatments in non-clinical settings.