Cardiotoxicity of chloroquine and hydroxychloroquine through mitochondrial pathway.

BACKGROUND: Medical therapies can cause cardiotoxicity. Chloroquine (QC) and hydroxychloroquine (HQC) are drugs used in the treatment of malaria and skin and rheumatic disorders. These drugs were considered to help treatment of coronavirus disease (COVID-19) in 2019. Despite the low cost and availability of QC and HQC, reports indicate that this class of drugs can cause cardiotoxicity. The mechanism of this event is not well known, but evidence shows that QC and HQC can cause cardiotoxicity by affecting mitochondria and lysosomes. METHODS: Therefore, our study was designed to investigate the effects of QC and HQC on heart mitochondria. In order to achieve this aim, mitochondrial function, reactive oxygen species (ROS) level, mitochondrial membrane disruption, and cytochrome c release in heart mitochondria were evaluated. Statistical significance was determined using the one-way and two-way analysis of variance (ANOVA) followed by post hoc Tukey to evaluate mitochondrial succinate dehydrogenase (SDH) activity and cytochrome c release, and Bonferroni test to evaluate the ROS level, mitochondrial membrane potential (MMP) collapse, and mitochondrial swelling. RESULTS: Based on ANOVA analysis (one-way), the results of mitochondrial SDH activity showed that the IC50 concentration for CQ is 20 µM and for HCQ is 50 µM. Based on two-way ANOVA analysis, the highest effect of CQ and HCQ on the generation of ROS, collapse in the MMP, and mitochondrial swelling were observed at 40 µM and 100 µM concentrations, respectively (p < 0.05). Also, the highest effect of these two drugs has been observed in 60 min (p < 0.05). The statistical results showed that compared to CQ, HCQ is able to cause the release of cytochrome c from mitochondria in all applied concentrations (p < 0.05). CONCLUSIONS: The results suggest that QC and HQC can cause cardiotoxicity which can lead to heart disorders through oxidative stress and disfunction of heart mitochondria.

Antiviral Effects of Hydroxychloroquine and Type I Interferon on In Vitro Fatal Feline Coronavirus Infection.

Feline infectious peritonitis (FIP) is a viral disease with a high morbidity and mortality by the FIP virus (FIPV, virulent feline coronavirus). Several antiviral drugs for FIP have been identified, but many of these are expensive and not available in veterinary medicine. Hydroxychloroquine (HCQ) is a drug approved by several countries to treat malaria and immune-mediated diseases in humans, and its antiviral effects on other viral infections (e.g., SARS-CoV-2, dengue virus) have been confirmed. We investigated whether HCQ in association with interferon-ω (IFN-ω) is effective for FIPV in vitro. A total of 100 µM of HCQ significantly inhibited the replication of types I and II FIPV. Interestingly, the combination of 100 µM of HCQ and 104 U/mL of recombinant feline IFN-ω (rfIFN-ω, veterinary registered drug) increased its antiviral activity against type I FIPV infection. Our study suggested that HCQ and rfIFN-ω are applicable for treatment of FIP. Further clinical studies are needed to verify the combination of HCQ and rIFN-ω will be effective and safe treatment for cats with FIP.

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.

Synthesis and evaluation of enantiomers of hydroxychloroquine against SARS-CoV-2 in vitro.

Since the end of 2019, the outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has evolved into a global pandemic. There is an urgent need for effective and low-toxic antiviral drugs to remedy Remdesivir's limitation. Hydroxychloroquine, a broad spectrum anti-viral drug, showed inhibitory activity against SARS-CoV-2 in some studies. Thus, we adopted a drug repurposing strategy, and further investigated hydroxychloroquine. We obtained different configurations of hydroxychloroquine side chains by using chiral resolution technique, and successfully furnished R-/S-hydroxychloroquine sulfate through chemical synthesis. The R configuration of hydroxychloroquine was found to exhibit higher antiviral activity (EC50 = 3.05 µM) and lower toxicity in vivo. Therefore, R-HCQ is a promising lead compound against SARS-CoV-2. Our research provides new strategy for the subsequent research on small molecule inhibitors against SARS-CoV-2.

Environmental impacts of COVID-19 treatment: Toxicological evaluation of azithromycin and hydroxychloroquine in adult zebrafish.

One of the most impact issues in recent years refers to the COVID-19 pandemic, the consequences of which thousands of deaths recorded worldwide, are still inferior understood. Its impacts on the environment and aquatic biota constitute a fertile field of investigation. Thus, to predict the impact of the indiscriminate use of azithromycin (AZT) and hydroxychloroquine (HCQ) in this pandemic context, we aim to assess their toxicological risks when isolated or in combination, using zebrafish (Danio rerio) as a model system. In summary, we observed that 72 h of exposure to AZT and HCQ (alone or in binary combination, both at 2.5 µg/L) induced the reduction of total protein levels, accompanied by increased levels of thiobarbituric acid reactive substances, hydrogen peroxide, reactive oxygen species and nitrite, suggesting a REDOX imbalance and possible oxidative stress. Molecular docking analysis further supported this data by demonstrating a strong affinity of AZT and HCQ with their potential antioxidant targets (catalase and superoxide dismutase). In the protein-protein interaction network analysis, AZT showed a putative interaction with different cytochrome P450 molecules, while HCQ demonstrated interaction with caspase-3. The functional enrichment analysis also demonstrated diverse biological processes and molecular mechanisms related to the maintenance of REDOX homeostasis. Moreover, we also demonstrated an increase in the AChE activity followed by a reduction in the neuromasts of the head when zebrafish were exposed to the mixture AZT + HCQ. These data suggest a neurotoxic effect of the drugs. Altogether, our study demonstrated that short exposure to AZT, HCQ or their mixture induced physiological alterations in adult zebrafish. These effects can compromise the health of these animals, suggesting that the increase of AZT and HCQ due to COVID-19 pandemic can negatively impact freshwater ecosystems.

Toxicity of hydroxychloroquine, a potential treatment for COVID-19, on free-living marine nematodes.

On March 2020, hydroxychloroquine (HCQ) was recommended as a treatment for COVID-19 high risk patients. Following the massive and widespread use of HCQ worldwide, a discernible high quantity is anticipated to end-up through the sewage systems in marine coastal areas. A closed microcosm study was undertaken herein for 30 days where meiobenthic nematodes were exposed to a range of HCQ concentrations (3.162, 31.62 and 63.24 µg.ml-1). After one month of exposure in HCQ, the total abundances and Shannon-Wiener index of the assemblages decreased, whereas the individual mass and the Trophic Diversity Index increased at the highest concentrations. Overall, a numerical negative impact was observed for the epistrate feeders and non-selective deposit feeders, however, this benefited to the omnivores-carnivores, and particularly to the Oncholaimids. Such responses of the nematodes 2B and the corresponding taxa are bioindicative of current- or post-COVID-19 crisis risks in relation with the bioaccumulation of HCQ in seafood.

What can visual caregivers expect with patients treated for SARS-CoV-2? An analysis of ongoing clinical trials and ocular side effects.

Within the COVID-19 pandemic context, the WHO has proposed a list of medicines to treat patients with severe acute respiratory syndrome (SARS-CoV-2). An analysis of their ocular side effects was performed. Only chloroquine and hydroxychloroquine were found to have an ocular impact in the medium and long-term. Detailed search strategies were performed in EMBASE, MEDLINE, SCOPUS and WOS Core Collection. Additionally, the worldwide ongoing clinical trials including chloroquine or hydroxychloroquine were evaluated, and their proposals of drug administration and exclusion criteria analyzed. In general, high maximum cumulative doses of chloroquine or hydroxychloroquine are being used for a short period in 135 currently underway clinical trials (to 21st April 2020). Typically, the doses were 2 to 5 times greater than the AAO recommendation (adjusted to weight) to avoid toxic retinopathy, the most undesirable ocular side effect. Maximum cumulative doses up to 12,000 mg for chloroquine and 18,000 mg for hydroxychloroquine were found. In prophylaxis clinical trials, 72,000 mg and 22,500 mg were the maximum cumulative doses for hydroxychloroquine and chloroquine respectively. Only 48% of the clinical trials considered retinal impairment as an exclusion criterion, and just one referred to an ophthalmic examination previous to study inclusion. How chloroquine and hydroxychloroquine treatment affect patients with a previous retinal condition is still poorly understood. A comprehensive ophthalmological examination 6 months after treatment is recommended in this subgroup. This review provides an overview of this topic and sheds light on the challenges visual caregivers may face regarding these repurposed drugs.

Toxicity of chloroquine and hydroxychloroquine following therapeutic use or overdose.

INTRODUCTION: While chloroquine, a derivative of quinine, has been used as an antimalarial for 70 years, hydroxychloroquine is now used to treat conditions such as rheumatoid arthritis and systemic lupus erythematosus. In 2020, hydroxychloroquine (and to a lesser extent chloroquine) also received attention as a possible treatment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). During investigation for treating coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2, concerns for serious adverse events arose. OBJECTIVE: We review the toxicity associated with hydroxychloroquine and chloroquine use both short-term and long-term and in overdose. METHODS: Medline (via OVID) was searched from its inception through June 7 2020 using the following as either MeSH or keyword terms: ("Chloroquine/" or "Hydroxychloroquine/") AND ("Adverse Drug Event/" or "Toxicities, Drug/" or "Toxic.mp." or "Toxicity.mp." or "Overdose.mp."). We limited resultant articles to those published in English and reporting on Human subjects. This search yielded 330 articles, of which 57 were included. Articles were excluded due to lack of relevance, not reporting desired outcomes, or being duplicative in their content. Twenty-five additional articles were identified through screening references of included articles. To identify toxicities in individuals treated with hydroxychloroquine or chloroquine with COVID-19, we searched PubMed on June 10th, 2020: ("Chloroquine" or "Hydroxychloroquine") AND ("Coronavirus" or "COVID-19" or "SARS-CoV-2"). This search resulted in 638 articles. We reviewed articles for reporting of adverse events or toxicities. Most citations were excluded because they did not include original investigations or extrapolated data from subjects that did not have COVID-19; 34 citations were relevant. For the drug-interactions section, relevant classes and agents were identified through a screen of the https://www.covid19-druginteractions.org/ website. We then conducted targeted searches of PubMed up to June 7th 2020 combining "chloroquine" and "hydroxychloroquine" with terms for specific drug classes and drugs identified from the drug-interaction site as potentially relevant. We found 29 relevant articles. TOXICITY WITH SHORT-TERM USE: Gastrointestinal: Gastrointestinal toxicities are the most common to occur following initiation of chloroquine or hydroxychloroquine. Nausea, vomiting, and diarrhea account for most reported intolerances. Glucose abnormalities: Alterations in blood glucose concentrations may occur with hydroxychloroquine but are rare with standard therapeutic use. Cardiotoxicity: Short-term use can produce conduction abnormalities. Evidence from COVID-19 treatment suggests QT/QTc prolongation is of concern, particularly when used in combination with azithromycin, although disagreement exists across studies. Dermatologic: Drug eruptions or rashes, followed by cutaneous hyperpigmentation, pruritis, Stevens-Johnson syndrome, and toxic epidermal necrolysis, may occur within days to weeks of exposure but usually resolve with the discontinuation of therapy. Neuropsychiatric: Reported symptoms include confusion, disorientation, and hallucination within 24-48 h of drug initiation. Other toxicities: Hemolysis and anemia may occur in patients with glucose-6-phosphate dehydrogenase. Chloroquine treatment of COVID-19 was associated with elevation in creatine kinase and creatine kinase-MB activities with more events in the higher-dose group. TOXICITY WITH LONG-TERM USE: Retinopathy: Retinopathy is the major dose-limiting toxicity associated with long-term use; the risk is higher with increasing age, dose, and duration of usage. Cardiotoxicity: Long-term use has been associated with conduction abnormalities, cardiomyopathy, and valvular disorders. Neurotoxicity: Rarely myositis and muscle weakness, extremity weakness, and pseudoparkinsonism have been reported. TOXICITY IN OVERDOSE: Symptoms in overdose manifest rapidly (minutes to hours) and cardiotoxicity such as cardiovascular shock and collapse are most prominent. Neurotoxic effects such as psychosis and seizure may also occur. CONCLUSIONS: Hydroxychloroquine is a generally well-tolerated medication. Short-term (days to weeks) toxicity includes gastrointestinal effects and rarely glucose abnormalities, dermatologic reactions, and neuropsychiatric events. Cardiotoxicity became of increased concern with its use in COVID-19 patients. Long-term (years) toxicities include retinopathy, neuromyotoxicity, and cardiotoxicity (conduction abnormalities, cardiomyopathy). Deaths from overdoses most often result from cardiovascular collapse.

Chloroquine kills hair cells in zebrafish lateral line and murine cochlear cultures: Implications for ototoxicity.

Hearing and balance deficits have been reported during and following treatment with the antimalarial drug chloroquine. However, experimental work examining the direct actions of chloroquine on mechanoreceptive hair cells in common experimental models is lacking. This study examines the effects of chloroquine on hair cells using two common experimental models: the zebrafish lateral line and neonatal mouse cochlear cultures. Zebrafish larvae were exposed to varying concentrations of chloroquine phosphate or hydroxychloroquine for 1 h or 24 h, and hair cells assessed by antibody staining. A significant, dose-dependent reduction in the number of surviving hair cells was seen across conditions for both exposure periods. Hydroxychloroquine showed similar toxicity. In mouse cochlear cultures, chloroquine damage was specific to outer hair cells in tissue from the cochlear basal turn, consistent with susceptibility to other ototoxic agents. These findings suggest a need for future studies employing hearing and balance monitoring during exposure to chloroquine and related compounds, particularly with interest in these compounds as therapeutics against viral infections including coronavirus.

Intentional Hydroxychloroquine Overdose Treated with High-Dose Diazepam: an Increasing Concern in the COVID-19 Pandemic.

INTRODUCTION: Recent attention on the possible use of hydroxychloroquine and chloroquine to treat COVID-19 disease has potentially triggered a number of overdoses from hydroxychloroquine. Toxicity from hydroxychloroquine manifests with cardiac conduction abnormalities, seizure activity, and muscle weakness. Recognizing this toxidrome and unique management of this toxicity is important in the COVID-19 pandemic. CASE REPORT: A 27-year-old man with a history of rheumatoid arthritis presented to the emergency department 7 hours after an intentional overdose of hydroxychloroquine. Initial presentation demonstrated proximal muscle weakness. The patient was found to have a QRS complex of 134 ms and QTc of 710 ms. He was treated with early orotracheal intubation and intravenous diazepam boluses. Due to difficulties formulating continuous diazepam infusions, we opted to utilize an intermitted intravenous bolus strategy that achieved similar effects that a continuous infusion would. The patient recovered without residual side effects. DISCUSSION: Hydroxychloroquine toxicity is rare but projected to increase in frequency given its selection as a potential modality to treat COVID-19 disease. It is important for clinicians to recognize the unique effects of hydroxychloroquine poisoning and initiate appropriate emergency maneuvers to improve the outcomes in these patients.

COVID-19 and toxicity from potential treatments: Panacea or poison.

Since December 2019, coronavirus disease (COVID-19) has been increasingly spreading from its origin in Wuhan, China to many countries around the world eventuating in morbidity and mortality affecting millions of people. This pandemic has proven to be a challenge given that there is no immediate cure, no vaccine is currently available and medications or treatments being used are still undergoing clinical trials. There have already been examples of self-medication and overdose. Clearly, there is a need to further define the efficacy of treatments used in the management of COVID-19. This evidence needs to be backed by large randomised-controlled clinical trials. In the meantime, there will no doubt be further off-label use of these medications by patients and practitioners and possibly related toxicity.

Cardiac safety of off-label COVID-19 drug therapy: a review and proposed monitoring protocol.

More than 2,000,000 individuals worldwide have had coronavirus 2019 disease infection (COVID-19), yet there is no effective medical therapy. Multiple off-label and investigational drugs, such as chloroquine and hydroxychloroquine, have gained broad interest due to positive pre-clinical data and are currently used for treatment of COVID-19. However, some of these medications have potential cardiac adverse effects. This is important because up to one-third of patients with COVID-19 have cardiac injury, which can further increase the risk of cardiomyopathy and arrhythmias. Adverse effects of chloroquine and hydroxychloroquine on cardiac function and conduction are broad and can be fatal. Both drugs have an anti-arrhythmic property and are proarrhythmic. The American Heart Association has listed chloroquine and hydroxychloroquine as agents which can cause direct myocardial toxicity. Similarly, other investigational drugs such as favipiravir and lopinavir/ritonavir can prolong QT interval and cause Torsade de Pointes. Many antibiotics commonly used for the treatment of patients with COVID-19, for instance azithromycin, can also prolong QT interval. This review summarizes evidenced-based data regarding potential cardiac adverse effects due to off-label and investigational drugs including chloroquine and hydroxychloroquine, antiviral therapy, monoclonal antibodies, as well as common antibiotics used for the treatment of COVID-19. The article focuses on practical points and offers a point-of-care protocol for providers who are taking care of patients with COVID-19 in an inpatient and outpatient setting. The proposed protocol is taking into consideration that resources during the pandemic are limited.

Chloroquine and Hydroxychloroquine Retinal Toxicity Consideration in the Treatment of COVID-19.

The proposed doses of chloroquine (CQ) and hydroxychloroquine (HCQ) for treatment of COVID-19 (1000 mg/day for 10 days, CQ; 800 mg first day then 400 mg/day for 5 days, HCQ) in many guidelines worldwide, are considerably higher than the maximum recommended daily safe doses of both agents (≤2.3 mg/kg/day, CQ; ≤5.0 mg/kg/day, HCQ) for development of retinal toxicity. Irreversible retinal damage can occur if the exposure to the safe doses is >5 years. It is not known whether exposure to high doses over a short period of time can also cause the damage. We recommend that before prescribing CQ or HCQ, history of ocular disease should be obtained to avoid the prescription if appropriate. If either agent is to be used, routine baseline ocular examination is not absolutely necessary. Patients who do not have ocular disease should also be informed about the potential risk of retinal toxicity. Both agents, however, have not yet been proven to be beneficial to COVID-19.

COVID-19: Therapeutics and Their Toxicities.

SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is causing the COVID-19 pandemic. There is no current standard of care. Clinicians need to be mindful of the toxicity of a wide variety of possibly unfamiliar substances being tested or repurposed to treat COVID-19. The United States Food and Drug Administration (FDA) has provided emergency authorization for the use of chloroquine and hydroxychloroquine. These two medications may precipitate ventricular dysrhythmias, necessitating cardiac and electrolyte monitoring, and in severe cases, treatment with epinephrine and high-doses of diazepam. Recombinant protein therapeutics may cause serum sickness or immune complex deposition. Nucleic acid vaccines may introduce mutations into the human genome. ACE inhibitors and ibuprofen have been suggested to exacerbate the pathogenesis of COVID-19. Here, we review the use, mechanism of action, and toxicity of proposed COVID-19 therapeutics.