Favipiravir induces oxidative stress and genotoxicity in cardiac and skin cells

Experimental evaluation of favipiravir (T-705)-induced liver and kidney toxicity in rats

Favipiravir is an antiviral drug that selectively and potently inhibits RNA-dependent RNA polymerase of various RNA viruses. Its empirical use has increased with the COVID-19 pandemic. This study aimed to investigate the potential toxicological effects of favipiravir administration on healthy rats' liver and kidney tissues. Four groups were established in the survey (n = 10): Control, Low-dose favipiravir (100 mg/kg/d), Medium-dose favipiravir (200 mg/kg/d), and High-dose favipiravir (300 mg/kg/d). On the first day of the study, a loading dose equivalent to twice the maintenance dose was administered. On the eleventh day, liver and kidney tissues were collected for histopathological and immunohistochemical analyses. According to our results, favipiravir caused various histopathological damages in the liver and kidneys and led to alterations in the levels of cytokines associated with inflammation (IL-6, TGF-β, TNF-α, IL-1β, IFN-γ). Co-administration of favipiravir with various protective agents may be needed to mitigate potential damage to the liver and kidneys.

Genotoxic risks in patients with COVID-19

The COVID-19 pandemic has caused numerous deaths worldwide. Despite the mitigation of infection manifestations in recent months, the possible consequences of the epidemic remain difficult to predict. Genotoxicity and subsequent development of neoplasms are possible outcomes. This review summarises the data on these questions. Studies from several countries have reported increased levels of DNA damage in nucleated blood cells of patients with severe forms of COVID-19 infection. The level of DNA damage can be used as a prognostic factor for the disease outcome. It is considered that SARS-CoV-2 spike proteins play a crucial role in DNA damage; however, the virus also inhibits the DNA repair system. Co-morbidities and use of antiviral drugs may also contribute to DNA damage in patients with COVID-19.

Investigation of metabolite profiles of kidney tissues in rats treated with favipiravir drug: An NMR-based metabolomics study

In response to the urgent need for effective treatments during the rapid spread and high mortality rate of COVID-19, existing drugs were repurposed for potential antiviral effects, including favipiravir, originally designed as an RNA-dependent RNA polymerase inhibitor for influenza. Despite limited antiviral effectiveness against COVID-19, favipiravir has been reported to cause several adverse drug events (ADEs) in the body. Recent studies have shown that favipiravir can damage various tissues in rats. However, a detailed analysis of its effects on the metabolomics profile of tissues using high-resolution spectroscopic technologies has not yet been conducted. In this study, it was aimed to analyze the metabolomic changes in rat kidney tissues induced by favipiravir, using high-resolution nuclear magnetic resonance (NMR) spectroscopy. Sixty male Wistar Albino rats were randomly divided into three groups: control, low-dose favipiravir (200 mg/kg), and high-dose favipiravir (300 mg/kg), with 20 rats per group. Each group received its respective treatment via oral gavage. After the treatment period, kidney tissue samples were collected and subjected to 1H NMR analysis. Bioinformatics analysis of the obtained 1H NMR spectra suggests that favipiravir induces dose-dependent metabolic changes in kidney tissue, with higher doses causing more profound disruptions in several pathways.

Evaluation of the effects of favipiravir (T-705) on the lung tissue of healty rats: An experimental study

Favipiravir, a broad-spectrum RNA-dependent RNA polymerase inhibitor widely used during the COVID-19 pandemic, effectively reduces viral load but has been linked to inflammatory changes in tissues such as the liver and kidneys. High-dose and prolonged use of favipiravir for COVID-19 raises concerns about its potential toxic effects on the lungs, particularly in patients with pre-existing pulmonary conditions. This study investigated favipiravir's effects on lung tissue in healthy rats. Experimental groups included a Control (saline) and three favipiravir doses: Low (200 mg/kg/day loading, 100 mg/kg/day maintenance), Medium (400 mg/kg/day loading, 200 mg/kg/day maintenance), and High (600 mg/kg/day loading, 300 mg/kg/day maintenance), all administered via gavage for 10 days. Histopathological analysis showed normal lung structure in the Control group, while favipiravir-treated groups exhibited Bronchus-Associated Lymphoid Tissue (BALT) enlargement, inflammation, fibrosis, and hemorrhage. Immunohistochemical analysis revealed dose-dependent increases in TNF-α, TGF-β, IL-6, IFN-γ, IL1-β, α-SMA, and collagen-1, especially in the High-dose group (p < 0.05). These findings suggest favipiravir may induce lung inflammation and fibrosis, emphasizing the need for careful evaluation of its safety in clinical settings, particularly for COVID-19 treatment. Future research should investigate the underlying mechanisms of these effects with clinical studies to assess their relevance to humans, high-risk pulmonary patients.

Favipiravir-induced bradycardia: A case report

Key Clinical Message

The purpose of this case report is to reveal one of the cardiovascular side effects of favipiravir, sinus bradycardia.

Abstract

Favipiravir has emerged as a potential treatment for COVID-19, with its antiviral properties showing promise in inhibiting viral replication. However, concerns regarding its safety profile, particularly its cardiac adverse effects, remain a subject of debate. We present the case of a 58-year-old man with a history of diabetes mellitus and chronic obstructive pulmonary disease who developed bradycardia following treatment with favipiravir for COVID-19 pneumonia. Despite being asymptomatic, the patient exhibited sinus bradycardia, which resolved upon discontinuation of favipiravir. Favipiravir has been associated with QT prolongation and sinus bradycardia, though the exact mechanisms remain unclear. Our case adds to the growing body of evidence highlighting the potential cardiac complications of favipiravir therapy in COVID-19 patients. Further research is warranted to clarify the underlying mechanisms and optimize patient management strategies. Clinicians should be cautious for cardiac adverse events when prescribing favipiravir for COVID-19 treatment, especially in patients with preexisting cardiac conditions. Continued research is essential to ensure the safe and effective use of favipiravir in the management of COVID-19.

Non-clinical safety assessment of Annona atemoya leaf extract: evaluation of genotoxicity

The leaves, stems, and fruits of Annona atemoya (A. atemoya; AA), a fruit-bearing plant of the family Annonaceae, exhibit anti-angiogenic, anti-oxidative, anti-inflammatory, and neuroprotective activities. However, the safety of AA has not been comprehensively elucidated. In this study, we evaluated the potential genotoxicity of an AA leaf (AAL) ethanol extract using a standard three-test battery constituting in vitro mammalian chromosomal aberration, in vivo micronucleus, and bacterial reverse mutation (also known as the Ames test) tests, as recommended by the Ministry of Food and Drug Safety of Korea. In vitro chromosomal aberration assay revealed that AAL extract did not induce structural or numerical aberrations, with or without metabolic activation (S9). In vivo micronucleus assay revealed that the number of micronucleated polychromatic erythrocytes (PCEs) and the PCE/normochromatic erythrocyte ratio after AAL extract treatment were not substantially different from those in the negative control. Changes in body weight and mortality were not observed. However, AAL extract partially induced mutagenic activity in all three bacterial strains in the bacterial reverse mutation assay, indicating that it could potentially aid in determining the genotoxic safety of AAL. QuantSeq 3' mRNA sequencing analysis to elucidate the genotoxicity mechanisms of AAL extract using TK6 cells revealed that the genotoxic effects of AAL may be associated with cellular morphology-associated (cell development and keratinization), nucleotide metabolism, and electron transport chain functions.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-024-00241-4.

Pharmacogenomic Studies of Antiviral Drug Favipiravir

In this work, we conducted a study of the interaction between DNA and favipiravir (FAV). This chemotherapeutic compound is an antiviral drug for the treatment of COVID-19 and other infections caused by RNA viruses. This paper examines the electroanalytical characteristics of FAV. The determined concentrations correspond to therapeutically significant ones in the range of 50-500 µM (R2 = 0.943). We have shown that FAV can be electro-oxidized around the potential of +0.96 V ÷ +0.98 V (vs. Ag/AgCl). A mechanism for electrochemical oxidation of FAV was proposed. The effect of the drug on DNA was recorded as changes in the intensity of electrochemical oxidation of heterocyclic nucleobases (guanine, adenine and thymine) using screen-printed graphite electrodes modified with single-walled carbon nanotubes and titanium oxide nanoparticles. In this work, the binding constants (Kb) of FAV/dsDNA complexes for guanine, adenine and thymine were calculated. The values of the DNA-mediated electrochemical decline coefficient were calculated as the ratio of the intensity of signals for the electrochemical oxidation of guanine, adenine and thymine in the presence of FAV to the intensity of signals for the electro-oxidation of these bases without drug (S, %). Based on the analysis of electrochemical parameters, values of binding constants and spectral data, intercalation was proposed as the principal mechanism of the antiviral drug FAV interaction with DNA. The interaction with calf thymus DNA also confirmed the intercalation mechanism. However, an additional mode of interaction, such as a damage effect together with electrostatic interactions, was revealed in a prolonged exposure of DNA to FAV.

Favipiravir biotransformation by a side-stream partial nitritation sludge: Transformation mechanisms, pathways and toxicity evaluation

Information on biotransformation of antivirals in the side-stream partial nitritation (PN) process was limited. In this study, a side-stream PN sludge was adopted to investigate favipiravir biotransformation under controlled ammonium and pH levels. Results showed that free nitrous acid (FNA) was an important factor that inhibited ammonia oxidation and the cometabolic biodegradation of favipiravir induced by ammonia oxidizing bacteria (AOB). The removal efficiency of favipiravir reached 12.6% and 35.0% within 6 days at the average FNA concentrations of 0.07 and 0.02 mg-N L-1, respectively. AOB-induced cometabolism was the sole contributing mechanism to favipiravir removal, excluding AOB-induced metabolism and heterotrophic bacteria-induced biodegradation. The growth of Escherichia coli was inhibited by favipiravir, while the AOB-induced cometabolism facilitated the alleviation of the antimicrobial activities with the formed transformation products. The biotransformation pathways were proposed based on the roughly identified structures of transformation products, which mainly involved hydroxylation, nitration, dehydrogenation and covalent bond breaking under enzymatic conditions. The findings would provide insights on enriching AOB abundance and enhancing AOB-induced cometabolism under FNA stress when targeting higher removal of antivirals during the side-stream wastewater treatment processes.

Favipiravir Analogues as Inhibitors of SARS-CoV-2 RNA-Dependent RNA Polymerase, Combined Quantum Chemical Modeling, Quantitative Structure-Property Relationship, and Molecular Docking Study

Our study was motivated by the urgent need to develop or improve antivirals for effective therapy targeting RNA viruses. We hypothesized that analogues of favipiravir (FVP), an inhibitor of RNA-dependent RNA polymerase (RdRp), could provide more effective nucleic acid recognition and binding processes while reducing side effects such as cardiotoxicity, hepatotoxicity, teratogenicity, and embryotoxicity. We proposed a set of FVP analogues together with their forms of triphosphate as new SARS-CoV-2 RdRp inhibitors. The main aim of our study was to investigate changes in the mechanism and binding capacity resulting from these modifications. Using three different approaches, QTAIM, QSPR, and MD, the differences in the reactivity, toxicity, binding efficiency, and ability to be incorporated by RdRp were assessed. Two new quantum chemical reactivity descriptors, the relative electro-donating and electro-accepting power, were defined and successfully applied. Moreover, a new quantitative method for comparing binding modes was developed based on mathematical metrics and an atypical radar plot. These methods provide deep insight into the set of desirable properties responsible for inhibiting RdRp, allowing ligands to be conveniently screened. The proposed modification of the FVP structure seems to improve its binding ability and enhance the productive mode of binding. In particular, two of the FVP analogues (the trifluoro- and cyano-) bind very strongly to the RNA template, RNA primer, cofactors, and RdRp, and thus may constitute a very good alternative to FVP.

Assessment of toxicological effects of favipiravir (T-705) on the lung tissue of rats: An experimental study

This study aimed to present new data on the side effects of favipiravir on healthy lung tissue and the respiratory system. In the study, two different durations (5 and 10 days) were preferred to determine the effect of favipiravir treatment due to clinical improvement rates of approximately 5 and 10 days during the use of favipiravir in COVID-19 patients. In addition, after 10 days of favipiravir treatment, animals were kept for 5 days without any treatment to determine the regeneration of lung tissues. Favipiravir was administered to rats by oral gavage at a daily dose of 200 mg/kg for 5 and 10 days, as in previous studies. At the end of the experiment, the histopathological and biochemical effects of favipiravir in the lung tissue were investigated. The data obtained from the study showed that favipiravir increased oxidative stress parameters, expression of apoptotic markers, and pro-inflammatory markers in lung tissue. Since malondialdehydes is an oxidant parameter, it increased in favipiravir-administered groups; It was determined that the antioxidant parameters glutathione, superoxide dismutase, glutathione peroxidase, and catalase decreased. Other markers used in the analysis are Bcl-2, Bax, NF-κB, interleukin (IL)-6, Muc1, iNOS, P2X7R, IL-6 and caspase-3. The levels of Bax, caspase-3, NF-κB, IL-6, Muc1, and P2X7R were increased in the Fav-treated groups compared with the control. However, the levels of Bcl-2 decreased in the Fav-treated groups. The present study proves that favipiravir, widely used today, causes side effects in lung tissue.

The effect of vitamin C supplementation on favipiravir-induced oxidative stress and proinflammatory damage in livers and kidneys of rats

Background: Favipiravir (FPV), an effective antiviral agent, is a drug used to treat influenza and COVID-19 by inhibiting the RNA-dependent RNA polymerase (RdRp) of RNA viruses. FPV has the potential to increase oxidative stress and organ damage. The purpose of this study was to demonstrate the oxidative stress and inflammation caused by FPV in the liver and kidneys of rats, as well as to investigate the curative effects of vitamin C (VitC).Methods: A total of 40 Sprague-Dawley male rats were randomly and equally divided into the following five groups: 1st; Control, 2nd; FPV = 20 mg/kg, 3rd; FPV = 100 mg/kg, 4th; FPV = 20 mg/kg + VitC (150 mg/kg), and 5th; FPV = 100 mg/kg + VitC (150 mg/kg) groups. Rats were given either FPV (orally) or FPV plus VitC (intramuscular) for 14 days. Rat blood, liver, and kidney samples were collected at 15 days to be analyzed for oxidative and histological changes.Results: FPV administration resulted in an increase in proinflammatory cytokines (TNF-α and IL-6) in the liver and kidney, as well as oxidative and histopathologic damage. FPV increased TBARS levels significantly (p < .05) and decreased GSH and CAT levels in liver and kidney tissues but had no effect on SOD activity. VitC supplementation significantly reduced TNF-a, IL-6, and TBARS levels while increasing GSH and CAT levels (p < .05). Furthermore, VitC significantly attenuated FPV-induced histopathological alterations associated with oxidative stress and inflammation in the liver and kidney tissues (p < .05).Conclusion: FPV caused liver and kidney damage in rats. In contrast, co-administration of FPV with VitC improved FPV-induced oxidative, pro-inflammatory, and histopathological changes.