Optimal balance of benefit versus risk for tafenoquine in the treatment of Plasmodium vivax malaria.

A single 300 mg dose of tafenoquine (an 8-aminoquinoline), in combination with a standard 3-day course of chloroquine, is approved in several countries for the radical cure (prevention of relapse) of Plasmodium vivax malaria in patients aged ≥ 16 years. Despite this, questions have arisen on the optimal dose of tafenoquine. Before the availability of tafenoquine, a 3-day course of chloroquine in combination with the 8-aminoquinoline primaquine was the only effective radical cure for vivax malaria. The World Health Organization (WHO)-recommended standard regimen is 14 days of primaquine 0.25 mg/kg/day or 7 days of primaquine 0.5 mg/kg/day in most regions, or 14 days of primaquine 0.5 mg/kg/day in East Asia and Oceania, however the long treatment courses of 7 or 14 days may result in poor adherence and, therefore, low treatment efficacy. A single dose of tafenoquine 300 mg in combination with a 3-day course of chloroquine is an important advancement for the radical cure of vivax malaria in patients without glucose-6-phosphate dehydrogenase (G6PD) deficiency, as the use of a single-dose treatment will improve adherence. Selection of a single 300 mg dose of tafenoquine for the radical cure of P. vivax malaria was based on collective efficacy and safety data from 33 studies involving more than 4000 trial participants who received tafenoquine, including over 800 subjects who received the 300 mg single dose. The safety profile of single-dose tafenoquine 300 mg is similar to that of standard-dosage primaquine 0.25 mg/kg/day for 14 days. Both primaquine and tafenoquine can cause acute haemolytic anaemia in individuals with G6PD deficiency; severe haemolysis can lead to anaemia, kidney damage, and, in some cases, death. Therefore, relapse prevention using an 8-aminoquinoline must be balanced with the need to avoid clinical haemolysis associated with G6PD deficiency. To minimize this risk, the WHO recommends G6PD testing for all individuals before the administration of curative doses of 8-aminoquinolines. In this article, the authors review key efficacy and safety data from the pivotal trials of tafenoquine and argue that the currently approved dose represents a favourable benefit-risk profile.

Identification of new risk factors for hydroxychloroquine and chloroquine retinopathy in systemic lupus erythematosus patients.

BACKGROUND: Long-term hydroxychloroquine (HCQ) or chloroquine (CQ) intake causes retinal toxicity in 0.3-8 % of patients with rheumatic diseases. Numerous risk factors have been described, eg, daily dose by weight, treatment duration, chronic kidney disease, concurrent tamoxifen therapy and pre-existing retinal or macular disease. However, those factors cannot explain the entire risk of developing antimalarial retinopathy. OBJECTIVE: This study was undertaken to identify new risk factors associated with HCQ or CQ retinopathy (QRNP) in systemic lupus erythematosus (SLE) patients. METHODS: This case-control (1:2) study compared SLE patients with QRNP (cases) to those without (controls). Controls were matched for sex and known QRNP risk factors: HCQ and/or CQ treatment duration (±1 year) and age (±5 year) at SLE diagnosis. RESULTS: Forty-eight cases were compared to 96 SLE controls. Multivariable logistic-regression analysis retained the following as independent determinants significantly associated with QRNP: concomitant selective serotonin-reuptake inhibitor (SSRI) or serotonin- and norepinephrine-reuptake inhibitor (SNRI) intake (OR [95 % confidence interval] 6.6 [1.2 to 40.9]; p < 0.01); antiphospholipid syndrome (OR=8.9 [2.2 to 41.4] p < 0.01); blood hydroxychloroquine/desethylchloroquine concentration ([HCQ]/[DCQ]) ratio <7.2 (OR 8.4 [2.7 to 30.8]; p < 0.01) or skin phototype ≥4 (OR 5.5 [1.4 to 26.5]; p = 0.02), but not daily HCQ dose, blood [HCQ] or body mass index. CONCLUSION: The results of this case-control study identified blood [HCQ]/[DCQ] ratio, concurrent SSRI/SNRI therapy, skin phototype ≥4 and antiphospholipid syndrome as new risk factors for QRNP.

Artemisinin-naphthoquine plus lower-dose primaquine to treat and prevent recurrence of Plasmodium vivax malaria: an open-label randomized and non-inferiority trial.

BACKGROUND: Plasmodium vivax malaria, with the widest geographic distribution, can cause severe disease and death. Primaquine is the main licensed antimalarial drug that can kill hypnozoites. The dose-dependent acute haemolysis in individuals with glucose-6-phospate dehydrogenase (G6PD) deficiency is the main safety concern when using primaquine. The recommended treatment regimen for P. vivax malaria is chloroquine plus primaquine for 14 days (CQPQ14) in Myanmar. The study aimed to evaluate the therapeutic efficacy, safety and adherence for the regimen of artemisinin-naphthoquine plus primaquine for 3 days (ANPQ3) in patients with P. vivax infections compared to those with CQPQ14. METHODS: The patients in the ANPQ3 group were given fixed-dose artemisinin-naphthoquine (a total 24.5 mg/kg bodyweight) plus a lower total primaquine dose (0.9 mg/kg bodyweight) for 3 days. The patients in the CQPQ14 group were given a total chloroquine dose of 30 mg/kg body weight for 3 days plus a total primaquine dose of 4.2 mg/kg bodyweight for 14 days. All patients were followed up for 365 days. RESULTS: A total of 288 patients completed follow-up, 172 in the ANPQ3 group and 116 in the CQPQ14 group. The first recurrence patients were detected by day 58 in both groups. By day 182, 16 recurrences had been recorded: 12 (7.0%) patients in the ANPQ3 group and 4 (3.4%) in the CQPQ14 group. The difference in recurrence-free patients was 3.5 (-8.6 to 1.5) percentage points between ANPQ3 and CQPQ14 group (P = 0.2946). By day 365, the percentage of recurrence-free patients was not significant between the two groups (P = 0.2257). Mean fever and parasite clearance time of ANPQ3 group were shorter than those in CQPQ14 group (P ≤ 0.001). No severe adverse effect was observed in ANPQ3 group, but five (3.9%) patients had acute haemolysis in CQPQ14 group (P = 0.013). Medication percentage of ANPQ3 group was significantly higher than that of CQPQ14 group (P < 0.0001). CONCLUSIONS: Both ANPQ3 and CQPQ14 promised clinical cure efficacy, and the radical cure efficacy was similar between the ANPQ3 and CQPQ14 group. ANPQ3 clears fever and parasites faster than CQPQ14. ANPQ3 is safer and shows better patient adherence to the regimen for treatment of P. vivax malaria along the China-Myanmar border. TRIAL REGISTRATION: ChiCTR-INR-17012523. Registered 31 August 2017, https://www.chictr.org.cn/showproj.html?proj=21352.

Pharmacogenomics of chloroquine and hydroxychloroquine: current evidence and future implications.

As substrates of CYP2C8, CYP3A4/5 and CYP2D6, chloroquine's (CQ) and hydroxychloroquine's (HCQ) efficacy and safety may be affected by variants in the genes encoding these enzymes. This paper aims to assimilate the current evidence on the pharmacogenomics of CQ/HCQ and to identify risk phenotypes affecting the safety or efficacy of these drugs. It has been found that some CYP3A5, CYP2D6 and CYP2C8 genetic variants may affect the safety or effectiveness of CQ/HCQ. The phenotypes predictively representing ultra-rapid and poor metabolizers have been considered high-risk phenotypes. After considering these high-risk phenotypes in different ethnic groups, it is predicted that a considerable proportion of patients taking CQ/HCQ may be at risk of either therapeutic failure or severe toxicities.

Preliminary Study on Open Labelled Randomized Controlled Trial of the Safety and Efficacy of Hydroxychloroquine and Chloroquine Phosphate for the Treatment of Persons Infected with 2019 Coronavirus Disease in Nigeria.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a causative agent of COVID-19 is a leading cause of ill-health and deaths worldwide. Currently, COVID-19 has no known widely approved therapeutics. Thus, the need for effective treatment. OBJECTIVES: We investigated the safety and efficacy of two (2) therapeutic agents; chloroquine phosphate (CQ), 2- hydroxychloroquine (HCQ) and a control (standard supportive therapy) among hospitalized adults with COVID-19. METHODS: The clinical trial was done in accordance to the World Health Organization master protocol for investigational therapeutics for COVID-19. Atotal of 40 participants with laboratory-confirmed positive COVID-19 were enrolled. Blood samples and oropharyngeal (OP) swabs were obtained on days 1,3,15 and 29 for safety and efficacy assessments. RESULTS: The baseline demographics showed that the median ages in years (range) were 45 (31-57) in CQ, 45 (36.5-60.5) in HCQ, 43 (39.5-67.0) and 44.5 (25.3-51.3) in the control (P<0.042).At randomization, seven (7) participants were asymptomatic, thirty-three (33) had mild symptoms, eight (8) had moderate symptoms while three (3) had severe symptoms. The average day of conversion to negative COVID-19 was 15.5 days for CQ, 16 days for HCQ and 18 days for the control(P=0.036). CONCLUSION: The safety assessment revealed no adverse effect of the drugs in COVID-19 patients after treatment. These findings proved that chloroquine and hydroxychloroquine are effective for the treatment of COVID-19 among hospitalized adults. It also confirmed that they are safe.

CONTEXTE: Le coronavirus du syndrome respiratoire aigu sévère 2 (SARS-CoV-2),agentcausaldelaCOVID-19, est l'unedes principales causes demaladie et de décès dans le monde. À l'heure actuelle, il n'existe aucun traitement largement approuvé pour la COVID-19. Ainsi, ilya un besoin de traitement efficace. OBJECTIFS: Nous avons étudié l'innocuité et l'efficacité de deux (2) agents thérapeutiques, le phosphate de chloroquine (CQ) et l'hydroxychloroquine (HCQ), ainsi qu'un groupe témoin (traitement de soutien standard) chez des adultes hospitalisés atteints de la COVID-19.MÉTHODES: L'essai clinique a été mené conformément au protocole maître de l'Organisation mondiale de la santé pour les thérapeutiques à l'étude de la COVID-19. Au total, 40 participants atteints de la COVID-19, confirmée en laboratoire, ont été in scrits. Des échantillons de sang et des prélèvements oropharyngés (PO) ont été effectuésauxjours1,3,15et29pourévaluerl'innocuitéetl'efficacité. RÉSULTATS: Les données démographiques initiales ont révélé que l'âge médian en années (plage) était de 45 (31-57) pour le groupe CQ, de 45 (36,5-60,5) pour le groupe HCQ, de 43 (39,5-67,0) et de 44,5 (25,3-51,3) pour le groupe témoin (P<0,042). À la randomisation, sept (7) participants étaient asymptomatiques, trente-trois (33) présentaient des symptômes bénins, huit(8) avaient des symptômes modérés, tandis que trois(3) avaient des symptômes graves. Le jour moyende conversionentest COVID-19 négatif était de 15,5 jours pour le groupe CQ, de 16 jours pour le groupe HCQ et de 18 jours pourle groupe témoin (P=0,036). CONCLUSION: L'évaluation de la sécurité n'a révélé aucun effet indésirable des médicaments chez les patients atteints de la COVID-19 après le traitement. Ces conclusions ont prouvé que la chloroquine et l'hydroxychloroquine sont efficaces pour le traitement de la COVID-19 chez les adultes hospitalisés. Cela a également confirmé qu' ilssont sûrs. Mots-clés: COVID-19, SARS-CoV-2, essai clinique, innocuité, efficacité, thérapeutiques.

Real-Life Data on Hydroxychloroquine or Chloroquine with or Without Azithromycin in COVID-19 Patients: A Retrospective Analysis in Brazil. / Dados de Vida Real sobre o Uso da Hidroxicloroquina ou da Cloroquina Combinadas ou Não à Azitromicina em Pacientes com Covid-19: Uma Análise Retrospectiva no Brasil.

BACKGROUND: Despite no evidence showing benefits of hydroxychloroquine and chloroquine with or without azithromycin for COVID-19 treatment, these medications have been largely prescribed in Brazil. OBJECTIVES: To assess outcomes, including in-hospital mortality, electrocardiographic abnormalities, hospital length-of-stay, admission to the intensive care unit, and need for dialysis and mechanical ventilation, in hospitalized COVID-19 patients who received chloroquine or hydroxychloroquine, and to compare outcomes between those patients and their matched controls. METHODS: A retrospective multicenter cohort study that included consecutive laboratory-confirmed COVID-19 patients from 37 Brazilian hospitals from March to September 2020. Propensity score was used to select matching controls by age, sex, cardiovascular comorbidities, and in-hospital use of corticosteroid. A p-value <0.05 was considered statistically significant. RESULTS: From 7,850 COVID-19 patients, 673 (8.6%) received hydroxychloroquine and 67 (0.9%) chloroquine. The median age in the study group was 60 years (46 - 71) and 59.1% were women. During hospitalization, 3.2% of patients presented side effects and 2.2% required therapy discontinuation. Electrocardiographic abnormalities were more prevalent in the chloroquine/hydroxychloroquine group (13.2% vs. 8.2%, p=0.01), and the long corrected QT interval was the main difference (3.6% vs. 0.4%, p<0.001). The median hospital length of stay was longer in the HCQ/CQ + AZT group than in controls (9.0 [5.0, 18.0] vs. 8.0 [4.0, 14.0] days). There was no statistical differences between groups in intensive care unit admission (35.1% vs. 32.0%; p=0.282), invasive mechanical ventilation support (27.0% vs. 22.3%; p=0.074) or mortality (18.9% vs. 18.0%; p=0.682). CONCLUSION: COVID-19 patients treated with chloroquine or hydroxychloroquine had a longer hospital length of stay, when compared to matched controls. Intensive care unit admission, invasive mechanical ventilation, dialysis and in-hospital mortality were similar.

FUNDAMENTO: Apesar da ausência de evidência mostrando benefícios da hidroxicloroquina e da cloroquina combinadas ou não à azitromicina no tratamento da covid-19, esses medicamentos têm sido amplamente prescritos no Brasil. OBJETIVOS: Avaliar desfechos, incluindo moralidade hospitalar, alterações eletrocardiográficas, tempo de internação, admissão na unidade de terapia intensiva, e necessidade de diálise e de ventilação mecânica em pacientes hospitalizados com covid-19 que receberam cloroquina ou hidroxicloroquina, e comparar os desfechos entre aqueles pacientes e seus controles pareados. MÉTODOS: Estudo multicêntrico retrospectivo do tipo coorte que incluiu pacientes com diagnóstico laboratorial de covid-19 de 37 hospitais no Brasil de março a setembro de 2020. Escore de propensão foi usado para selecionar controles pareados quanto a idade, sexo, comorbidades cardiovasculares, e uso de corticosteroides durante a internação. Um valor de p<0,05 foi considerado estatisticamente significativo. RESULTADOS: Dos 7850 pacientes com covid-19, 673 (8,6%) receberam hidroxicloroquina e 67 (0,9%) cloroquina. A idade mediana no grupo de estudo foi 60 (46-71) anos e 59,1% eram mulheres. Durante a internação, 3,2% dos pacientes apresentaram efeitos adversos e 2,2% necessitaram de interromper o tratamento. Alterações eletrocardiográficas foram mais prevalentes no grupo hidroxicloroquina/cloroquina (13,2% vs. 8,2%, p=0,01), e o prolongamento do intervalo QT corrigido foi a principal diferença (3,6% vs. 0,4%, p<0,001). O tempo mediano de internação hospitalar foi maior no grupo usando CQ/HCQ em relação aos controles (9,0 [5,0-18,0] vs. 8,0 [4,0-14,0] dias). Não houve diferenças estatisticamente significativas entre os grupos quanto a admissão na unidade de terapia intensiva (35,1% vs. 32,0%; p=0,282), ventilação mecânica invasiva (27,0% vs. 22,3%; p=0,074) ou mortalidade (18,9% vs. 18,0%; p=0,682). CONCLUSÃO: Pacientes com covid-19 tratados com cloroquina ou hidroxicloroquina apresentaram maior tempo de internação hospitalar, em comparação aos controles. Não houve diferença em relação a admissão em unidade de terapia intensiva, necessidade de ventilação mecânica e mortalidade hospitalar.

Quantitative Fundus Autofluorescence in Systemic Chloroquine/Hydroxychloroquine Therapy: One Year Follow-Up.

Purpose: Systemic chloroquine/hydroxychloroquine (CQ/HCQ) can cause severe ocular side effects including bull's eye maculopathy (BEM). Recently, we reported higher quantitative autofluorescence (QAF) levels in patients with CQ/HCQ intake. Here, QAF in patients taking CQ/HCQ in a 1-year follow-up is reported. Methods: Fifty-eight patients currently or previously treated with CQ/HCQ (cumulative doses 94-2435 g) and 32 age- and sex-matched healthy subjects underwent multimodal retinal imaging (infrared, red free, fundus autofluorescence [FAF], QAF [488 nm], and spectral-domain optical coherence tomography (SD-OCT). For analysis, custom written FIJI plugins were used for image processing, multimodal image stacks assembling, and QAF calculation. Results: Thirty patients (28 without BEM and 2 with BEM, age range = 25-69 years) were followed up (370 ± 63 days). QAF values in patients taking CQ/HCQ showed a significant increase between baseline and follow-up examination: 282.0 ± 67.9 to 297.7 ± 70.0 (QAF a.u.), P = 0.002. An increase up to 10% was observed in the superior macular hemisphere. Eight individuals (including 1 patient with BEM) had a pronounced QAF increase of up to 25%. Compared to healthy controls, QAF levels in patients taking CQ/HCQ were significantly increased (P = 0.04). Conclusions: Our study confirms our previous finding of increased QAF in patients taking CQ/HCQ with a further significant QAF increase from baseline to follow-up. Whether pronounced QAF increase might predispose for rapid progression toward structural changes and BEM development is currently investigated in ongoing studies. Translational Relevance: In addition to standard screening tools during systemic CQ/HCQ treatment, QAF imaging might be useful in CQ/HCQ monitoring and could serve as a screening tool in the future.

Adverse drug reactions to chloroquine/hydroxychloroquine in combination with azithromycin in COVID-19 in-patients: data from intensive pharmacovigilance in Morocco, 2020.

In Morocco, chloroquine/hydroxychloroquine + azithromycin have been used off-label for COVID-19 treatment. This study aimed to describe the distribution, nature and seriousness of the adverse drug reactions (ADRs) associated with the two drug combinations in COVID-19 in-patients. We conducted a prospective observational study based on intensive pharmacovigilance in national COVID-19 patients' management facilities from April 1 to June 12, 2020. Hospitalized patients treated with chloroquine/hydroxychloroquine + azithromycin and who experienced ADRs during their hospital stay were included in the study. The causality and seriousness of the ADRs were assessed using the World Health Organization-Uppsala Monitoring Centre method and the agreed criteria in the ICH guideline (E2A) respectively. A total of 237 (51.7%) and 221 (48.3%) COVID-19 in-patients treated respectively with chloroquine + azithromycin and hydroxychloroquine + azithromycin experienced 946 ADRs. Serious ADRs occurred in 54 patients (11.8%). Gastrointestinal system was most affected both in patients taking chloroquine + azithromycin (49.8%) or hydroxychloroquine + azithromycin (54.2%), followed by nervous system and psychiatric. Eye disorders were more frequent in patients receiving chloroquine + azithromycin (10.3%) than those receiving hydroxychloroquine + azithromycin (1.2%). Cardiac ADRs accounted for 6.4% and 5.1% respectively. Chloroquine + azithromycin caused more ADRs by patients than hydroxychloroquine + azithromycin (2.6 versus 1.5 ADRs/patient). Causality assessment was possible for 75.7% of the ADRs. Diabetes was identified as a risk factor for serious ADRs (ORa 3.56; IC: 95% 1.5-8.6). The off-label use of the two drug combinations in COVID-19 in-patients according to the national therapeutic protocol seems to be safe and tolerable. ADRs were mainly expected. However, precaution should be taken in using the drugs in diabetic patients to prevent the risk of serious ADRs.

Hydroxychloroquine for Non-Hospitalized COVID-19 Patients: A Systematic Review and Meta-Analysis of Randomized Clinical Trials. / Hidroxicloroquina para Pacientes com COVID-19 não Hospitalizados: Uma Revisão Sistemática e Metanálise de Ensaios Clínicos Randomizados.

BACKGROUND: Previous systematic reviews have identified no benefit of hydroxychloroquine and chloroquine in non-hospitalized COVID-19 patients. After publication of these reviews, the results of COPE, the largest randomized trial conducted to date, became available. OBJECTIVES: To conduct a systematic review and meta-analyses of randomized clinical trials (RCTs) to synthesize the evidence on the efficacy and safety of hydroxychloroquine and chloroquine for non-hospitalized COVID-19 patients compared to placebo or standard of care. METHODS: Searches were conducted in PubMed, Embase, The Cochrane Library, and ClinicalTrials.gov complemented by manual search. Pairwise meta-analyses, risk of bias, and evidence certainty assessments were conducted, including optimal information size analysis (OIS). A level of significance of 0.05 was adopted in the meta-analysis. PROSPERO: CRD42021265427. RESULTS: Eight RCTs with 3,219 participants were included. COVID-19 hospitalization and any adverse events rates were not significantly different between hydroxychloroquine (5.6% and 35.1%) and control (7.4% and 20.4%) (risk ratio, RR, 0.77, 95% confidence interval, CI, 0.57-1.04, I2: 0%; RR 1.78, 95%-CI 0.90; 3.52, I2: 93%, respectively). The OIS (7,880) was not reached for COVID-19 hospitalization, independently of the simulation for anticipated event rate and RR reduction estimate. CONCLUSION: Evidence of very low certainty showed lack of benefit with hydroxychloroquine in preventing COVID-19 hospitalizations. Despite being the systematic review with the largest number of participants included, the OIS, considering pre-vaccination response to infection, has not yet been reached.

FUNDAMENTO: Revisões sistemáticas anteriores não identificaram benefício do uso da hidroxicloroquina ou da cloroquina em pacientes com COVID-19 não hospitalizados. Após a publicação dessas revisões, os resultados do COPE, o maior ensaio clínico randomizado até hoje, tornaram-se disponíveis. OBJETIVOS: Conduzir uma revisão sistemática e metanálise de ensaios clínicos randomizados (ECRs) para sintetizar as evidências sobre a eficácia e a segurança da hidroxicloroquina e da cloroquina em pacientes com COVID-19 não hospitalizados em comparação a controle ou tratamento padrão. MÉTODOS: As buscas foram conduzidas nos bancos de dados PubMed, Embase, The Cochrane Library e ClinicalTrials.gov, e complementadas por busca manual. Foram realizadas metanálises diretas e avaliações de risco de viés e certeza da evidência, incluindo análise do tamanho ótimo da informação (OIS, optimal information size). Um nível de significância de 0,05 foi adotado na metanálise. PROSPERO: CRD42021265427. RESULTADOS: Oito ECRs com 3219 participantes foram incluídos. As taxas de internação por COVID-19 e de eventos adversos não foram significativamente diferentes entre hidroxicloroquina (5,6% e 5,1%) e controle (7,4% e 20,4%) [risco relativo (RR) 0,77, intervalo de confiança 95% (IC95%), 0,57-1,04, I2: 0%; RR 1,78, IC95% 0,90; 3,52, I2: 93%, respectivamente)]. O OIS (7880) não foi alcançado para hospitalização por COVID-19, independentemente da simulação para a taxa de evento e redução do RR estimados. CONCLUSÃO: A evidência de muito baixa qualidade indicou falta de benefício com hidroxicloroquina em prevenir internações por COVID-19. Apesar de ser a revisão sistemática com o maior número de participantes incluídos, o OIS, considerando a resposta à infecção anterior à vacinação, não foi atingido.

Molecular mechanisms of MrgprA3-independent activation of the transient receptor potential ion channels TRPA1 and TRPV1 by chloroquine.

BACKGROUND AND PURPOSE: Itch is associated with several pathologies and is a common drug-induced side effect. Chloroquine (CQ) is reported to induce itch by activating the Mas-related G protein-coupled receptor MrgprA3 and subsequently TRPA1. In this study, we demonstrate that CQ employs at least two MrgprA3-independent mechanisms to activate or sensitize TRPA1 and TRPV1. EXPERIMENTAL APPROACH: Patch clamp and calcium imaging were utilized to examine effects of CQ on TRPA1 and TRPV1 expressed in HEK 293T cells. KEY RESULTS: In calcium imaging, CQ induces a concentration-dependent but MrgprA3-independent activation of TRPA1 and TRPV1. Although CQ itself inhibits TRPA1 and TRPV1 in patch clamp recordings, co-application of CQ and ultraviolet A (UVA) light evokes membrane currents through both channels. This effect is inhibited by the reducing agent dithiothreitol (DTT) and is reduced on mutants lacking cysteine residues accounting for reactive oxygen species (ROS) sensitivity. The combination of CQ and UVA light triggers an accumulation of intracellular ROS, removes fast inactivation of voltage-gated sodium currents and activates TRPV2. On the other hand, CQ is a weak base and induces intracellular alkalosis. Intracellular alkalosis can activate TRPA1 and TRPV1, and CQ applied at alkaline pH values indeed activates both channels. CONCLUSION AND IMPLICATIONS: Our data reveal novel pharmacological properties of CQ, allowing activation of TRPA1 and TRPV1 via photosensitization as well as intracellular alkalosis. These findings add more complexity to the commonly accepted dogma that CQ-induced itch is specifically mediated by MrgprA3 coupling to TRPA1.

Systematic Review of Psychiatric Adverse Effects Induced by Chloroquine and Hydroxychloroquine: Case Reports and Population Studies.

OBJECTIVE: To perform a systematic review on the psychiatric adverse effects of chloroquine (CQ) and hydroxychloroquine (HCQ); to summarize what is known about psychiatric adverse effects of these drugs; to compare clinical trials, populational studies, and case report studies; and to increase awareness of the potential psychiatric adverse effects of these drugs. DATA SOURCES: A literature search of PubMed, Scopus, and Web of Science was performed to identify manuscripts published between December 1962 and June 2022. Search terms included CQ, HCQ, psychiatry, psychosis, depression, anxiety, bipolar disorder, delirium, and psychotic disorders. STUDY SELECTION AND DATA EXTRACTION: Relevant studies included reports of adverse effects after CQ or HCQ ingestion. DATA SYNTHESIS: The current literature presents evidence for a risk of short-term psychiatric adverse effects induced by either CQ or HCQ. However, the populational-level studies presented some limitations regarding the voluntary response in survey data, self-report adverse effects, and placebo group reporting similar symptoms to the case group. Thus, populational-level studies addressing the discussed limitations and the nature and extent of possible psychiatric adverse effects are needed. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: Most of the patients who developed such adverse effects did not report a family history of psychiatric disease. The frequency of psychiatric adverse effects depends on the patient's biological sex, age, and body mass index, but not on the drug dosage. CONCLUSIONS: Based on clinical trials and case reports, the current literature presents evidence for a risk of short-term psychiatric adverse effects induced by either drug.

How toxic is an old friend? A review of the safety of hydroxychloroquine in clinical practice.

Hydroxychloroquine (HCQ) and its close relative chloroquine (CQ) were initially used as antimalarial agents but are now widely prescribed in rheumatology, dermatology and immunology for the management of autoimmune diseases. HCQ is considered to have a better long-term safety profile than CQ and is therefore more commonly used. HCQ has a key role in the treatment of connective tissue diseases including systemic lupus erythematosus (SLE), where it provides beneficial immunomodulation without clinically significant immunosuppression. HCQ can also assist in managing inflammatory arthritis, including rheumatoid arthritis (RA). Debate around toxicity of HCQ in COVID-19 has challenged those who regularly prescribe HCQ to discuss its potential toxicities. Accordingly, we have reviewed the adverse effect profile of HCQ to provide guidance about this therapeutic agent in clinical practice.

The investigation of the complex population-drug-drug interaction between ritonavir-boosted lopinavir and chloroquine or ivermectin using physiologically-based pharmacokinetic modeling.

OBJECTIVES: Therapy failure caused by complex population-drug-drug (PDDI) interactions including CYP3A4 can be predicted using mechanistic physiologically-based pharmacokinetic (PBPK) modeling. A synergy between ritonavir-boosted lopinavir (LPVr), ivermectin, and chloroquine was suggested to improve COVID-19 treatment. This work aimed to study the PDDI of the two CYP3A4 substrates (ivermectin and chloroquine) with LPVr in mild-to-moderate COVID-19 adults, geriatrics, and pregnancy populations. METHODS: The PDDI of LPVr with ivermectin or chloroquine was investigated. Pearson's correlations between plasma, saliva, and lung interstitial fluid (ISF) levels were evaluated. Target site (lung epithelial lining fluid [ELF]) levels of ivermectin and chloroquine were estimated. RESULTS: Upon LPVr coadministration, while the chloroquine plasma levels were reduced by 30, 40, and 20%, the ivermectin plasma levels were increased by a minimum of 425, 234, and 453% in adults, geriatrics, and pregnancy populations, respectively. The established correlation equations can be useful in therapeutic drug monitoring (TDM) and dosing regimen optimization. CONCLUSIONS: Neither chloroquine nor ivermectin reached therapeutic ELF levels in the presence of LPVr despite reaching toxic ivermectin plasma levels. PBPK modeling, guided with TDM in saliva, can be advantageous to evaluate the probability of reaching therapeutic ELF levels in the presence of PDDI, especially in home-treated patients.

Berbamine Reduces Chloroquine-Induced Itch in Mice through Inhibition of MrgprX1.

Chloroquine (CQ) is an antimalaria drug that has been widely used for decades. However, CQ-induced pruritus remains one of the major obstacles in CQ treatment for uncomplicated malaria. Recent studies have revealed that MrgprX1 plays an essential role in CQ-induced itch. To date, a few MrgprX1 antagonists have been discovered, but they are clinically unavailable or lack selectivity. Here, a cell-based high-throughput screening was performed to identify novel antagonists of MrgprX1, and the screening of 2543 compounds revealed two novel MrgprX1 inhibitors, berbamine and closantel. Notably, berbamine potently inhibited CQ-mediated MrgprX1 activation (IC50 = 1.6 µM) but did not alter the activity of other pruritogenic GPCRs. In addition, berbamine suppressed the CQ-mediated phosphorylation of ERK1/2. Interestingly, CQ-induced pruritus was significantly reduced by berbamine in a dose-dependent manner, but berbamine had no effect on histamine-induced, protease-activated receptors 2-activating peptide-induced, and deoxycholic acid-induced itch in mice. These results suggest that berbamine is a novel, potent, and selective antagonist of MrgprX1 and may be a potential drug candidate for the development of therapeutic agents to treat CQ-induced pruritus.

Historical 8-Aminoquinoline Combinations: Not All Antimalarial Drugs Work Well Together.

Since their first use in the 1920s, 8-aminoquinolines have been known to have important toxicities such as methemoglobinemia and hemolysis. An empiric pamaquine (plasmochin) combination with quinine was widely used in the British military with relatively little toxicity. Attempts to use pamaquine with a new synthetic antimalarial drug (atabrine, quinacrine) in the 1930-1940s, however, resulted in hemolytic reactions and some deaths from renal failure. An improved 8-aminoquinoline, primaquine, was particularly effective against Plasmodium vivax relapses when combined with either quinine or chloroquine. When used in reduced daily doses (15 mg) over 2 weeks, it was safely given to many thousands of U.S. soldiers returning from Korea. CP tablets (chloroquine 300 mg, primaquine 45 mg weekly) were widely used during the Vietnam War with few hemolytic reactions and no known deaths. Efficacy and toxicity of 8-aminoquinolines is determined in part by the selection of appropriate partner drugs.

Hydroxychloroquine/chloroquine for the treatment of hospitalized patients with COVID-19: An individual participant data meta-analysis.

BACKGROUND: Results from observational studies and randomized clinical trials (RCTs) have led to the consensus that hydroxychloroquine (HCQ) and chloroquine (CQ) are not effective for COVID-19 prevention or treatment. Pooling individual participant data, including unanalyzed data from trials terminated early, enables more detailed investigation of the efficacy and safety of HCQ/CQ among subgroups of hospitalized patients. METHODS: We searched ClinicalTrials.gov in May and June 2020 for US-based RCTs evaluating HCQ/CQ in hospitalized COVID-19 patients in which the outcomes defined in this study were recorded or could be extrapolated. The primary outcome was a 7-point ordinal scale measured between day 28 and 35 post enrollment; comparisons used proportional odds ratios. Harmonized de-identified data were collected via a common template spreadsheet sent to each principal investigator. The data were analyzed by fitting a prespecified Bayesian ordinal regression model and standardizing the resulting predictions. RESULTS: Eight of 19 trials met eligibility criteria and agreed to participate. Patient-level data were available from 770 participants (412 HCQ/CQ vs 358 control). Baseline characteristics were similar between groups. We did not find evidence of a difference in COVID-19 ordinal scores between days 28 and 35 post-enrollment in the pooled patient population (odds ratio, 0.97; 95% credible interval, 0.76-1.24; higher favors HCQ/CQ), and found no convincing evidence of meaningful treatment effect heterogeneity among prespecified subgroups. Adverse event and serious adverse event rates were numerically higher with HCQ/CQ vs control (0.39 vs 0.29 and 0.13 vs 0.09 per patient, respectively). CONCLUSIONS: The findings of this individual participant data meta-analysis reinforce those of individual RCTs that HCQ/CQ is not efficacious for treatment of COVID-19 in hospitalized patients.

Review of Hydroxychloroquine Cardiotoxicity: Lessons From the COVID-19 Pandemic.

PURPOSE OF REVIEW: The coronavirus disease 2019 (COVID-19) pandemic has popularized the usage of hydroxychloroquine and chloroquine (HCQ/CQ) as treatments for COVID-19. Previously used as anti-malarial and now commonly used in rheumatologic conditions, preliminary in vitro studies have demonstrated these medications also have anti-viral properties. Retinopathy and neuromyopathy are well recognized complications of using these treatments; however, cardiotoxicity is under-recognized. This review will discuss the implications and cardiotoxicity of HCQ/CQ, their mechanisms of action, and their utility in COVID-19. RECENT FINDINGS: Early clinical trials demonstrated a modest benefit of HCQ in COVID-19, causing a push for the usage of it. However, further large multi-center randomized control centers, demonstrated no benefit, and even a trend towards worse outcomes. The predominant cardiac complication observed with HCQ in COVID-19 was cardiac arrhythmias and prolonging of the QT interval. However, with chronic usage of HCQ/CQ, the development of heart failure (HF) and cardiomyopathy (CM) can occur. Although, most adverse cardiac events related to HCQ/CQ usage in COVID-19 were secondary to conduction disorders given the short duration of treatment, HCQ/CQ can cause CM and HF, with chronic usage. Given the insufficient evidence, HCQ/CQ usage in COVID-19 is not routinely recommended, especially with novel therapies now being developed and used. Additionally, usage of HCQ/CQ should prompt initial cardiac evaluation with ECG, and yearly monitoring, with consideration for advanced imaging if clinically warranted. The diagnosis of HCQ/CQ cardiomyopathy is important, as prompt cessation can allow for recovery when these changes are still reversible.

Diagnosis, Treatment, and Prevention of Malaria in the US: A Review.

Importance: Malaria is caused by protozoa parasites of the genus Plasmodium and is diagnosed in approximately 2000 people in the US each year who have returned from visiting regions with endemic malaria. The mortality rate from malaria is approximately 0.3% in the US and 0.26% worldwide. Observations: In the US, most malaria is diagnosed in people who traveled to an endemic region. More than 80% of people diagnosed with malaria in the US acquired the infection in Africa. Of the approximately 2000 people diagnosed with malaria in the US in 2017, an estimated 82.4% were adults and about 78.6% were Black or African American. Among US residents diagnosed with malaria, 71.7% had not taken malaria chemoprophylaxis during travel. In 2017 in the US, P falciparum was the species diagnosed in approximately 79% of patients, whereas P vivax was diagnosed in an estimated 11.2% of patients. In 2017 in the US, severe malaria, defined as vital organ involvement including shock, pulmonary edema, significant bleeding, seizures, impaired consciousness, and laboratory abnormalities such as kidney impairment, acidosis, anemia, or high parasitemia, occurred in approximately 14% of patients, and an estimated 0.3% of those receiving a diagnosis of malaria in the US died. P falciparum has developed resistance to chloroquine in most regions of the world, including Africa. First-line therapy for P falciparum malaria in the US is combination therapy that includes artemisinin. If P falciparum was acquired in a known chloroquine-sensitive region such as Haiti, chloroquine remains an alternative option. When artemisinin-based combination therapies are not available, atovaquone-proguanil or quinine plus clindamycin is used for chloroquine-resistant malaria. P vivax, P ovale, P malariae, and P knowlesi are typically chloroquine sensitive, and treatment with either artemisinin-based combination therapy or chloroquine for regions with chloroquine-susceptible infections for uncomplicated malaria is recommended. For severe malaria, intravenous artesunate is first-line therapy. Treatment of mild malaria due to a chloroquine-resistant parasite consists of a combination therapy that includes artemisinin or chloroquine for chloroquine-sensitive malaria. P vivax and P ovale require additional therapy with an 8-aminoquinoline to eradicate the liver stage. Several options exist for chemoprophylaxis and selection should be based on patient characteristics and preferences. Conclusions and Relevance: Approximately 2000 cases of malaria are diagnosed each year in the US, most commonly in travelers returning from visiting endemic areas. Prevention and treatment of malaria depend on the species and the drug sensitivity of parasites from the region of acquisition. Intravenous artesunate is first-line therapy for severe malaria.