1
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El Harchi A, Hancox JC. hERG agonists pose challenges to web-based machine learning methods for prediction of drug-hERG channel interaction. J Pharmacol Toxicol Methods 2023; 123:107293. [PMID: 37468081 DOI: 10.1016/j.vascn.2023.107293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 05/23/2023] [Accepted: 07/12/2023] [Indexed: 07/21/2023]
Abstract
Pharmacological blockade of the IKr channel (hERG) by diverse drugs in clinical use is associated with the Long QT Syndrome that can lead to life threatening arrhythmia. Various computational tools including machine learning models (MLM) for the prediction of hERG inhibition have been developed to facilitate the throughput screening of drugs in development and optimise thus the prediction of hERG liabilities. The use of MLM relies on large libraries of training compounds for the quantitative structure-activity relationship (QSAR) modelling of hERG inhibition. The focus on inhibition omits potential effects of hERG channel agonist molecules and their associated QT shortening risk. It is instructive, therefore, to consider how known hERG agonists are handled by MLM. Here, two highly developed online computational tools for the prediction of hERG liability, Pred-hERG and HergSPred were probed for their ability to detect hERG activator drug molecules as hERG interactors. In total, 73 hERG blockers were tested with both computational tools giving overall good predictions for hERG blockers with reported IC50s below Pred-hERG and HergSPred cut-off threshold for hERG inhibition. However, for compounds with reported IC50s above this threshold such as disopyramide or sotalol discrepancies were observed. HergSPred identified all 20 hERG agonists selected as interacting with the hERG channel. Further studies are warranted to improve online MLM prediction of hERG related cardiotoxicity, by explicitly taking into account channel agonism as well as inhibition.
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Affiliation(s)
- Aziza El Harchi
- School of Physiology and Pharmacology and Neuroscience, Biomedical Sciences Building, The University of Bristol, University Walk, Bristol BS8 1TD, UK.
| | - Jules C Hancox
- School of Physiology and Pharmacology and Neuroscience, Biomedical Sciences Building, The University of Bristol, University Walk, Bristol BS8 1TD, UK
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2
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Macháček M, Švecová O, Bébarová M. Combination of Sildenafil and Ba2+ at a Low Concentration Show a Significant Synergistic Inhibition of Inward Rectifier Potassium Current Resulting in Action Potential Prolongation. Front Pharmacol 2022; 13:829952. [PMID: 35548367 PMCID: PMC9081525 DOI: 10.3389/fphar.2022.829952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 04/05/2022] [Indexed: 11/29/2022] Open
Abstract
Sildenafil (Viagra) is a vasodilator mainly used in the treatment of erectile dysfunction. Atrial or ventricular fibrillation may rarely occur as a side effect during sildenafil therapy. Although changes in inward rectifier potassium currents including IK1 are known to contribute to the pathogenesis of fibrillation, the effect of sildenafil on IK1 has not been studied. In experiments, Ba2+ is used as a specific inhibitor of IK1 at high concentrations (usually 100 µM). Being an environmental contaminant, it is also present in the human body; Ba2+ plasmatic concentrations up to 1.5 µM are usually reported in the general population. This study was primarily aimed to investigate changes of IK1 induced by sildenafil in a wide range of concentrations (0.1–100 µM). Additionally, the effect of combination of sildenafil and Ba2+ at selected clinically-relevant concentrations was tested, at 0.1 µM both on IK1 and on the action potential duration (APD). Experiments were performed by the whole-cell patch-clamp technique on enzymatically isolated rat ventricular cardiomyocytes, mostly at 23°C with the exception of APD measurements which were performed at 37°C as well. Sildenafil caused a significant, reversible, and concentration-dependent inhibition of IK1 that did not differ at −50 and −110 mV. Simultaneous application of sildenafil and Ba2+ at 0.1 µM revealed a massive inhibition of both inward and outward components of IK1 (this synergy was missing at other tested combinations). The combined effect at 0.1 µM (45.7 ± 5.7 and 43.0 ± 6.9% inhibition at −50 and −110 mV, respectively) was significantly higher than a simple sum of almost negligible effects of the individual substances and it led to a significant prolongation of APD at both 23 and 37°C. To our knowledge, similar potentiation of the drug-channel interaction has not been described. The observed massive inhibition of IK1 induced by a combined action of the vasodilator sildenafil and environmental contaminant Ba2+ at a low concentration and resulting in a significant APD prolongation may contribute to the genesis of arrhythmias observed in some patients treated with sildenafil.
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3
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Lin YK, Cheng CC, Huang JH, Chen YA, Lu YY, Chen YC, Chen SA, Chen YJ. Various subtypes of phosphodiesterase inhibitors differentially regulate pulmonary vein and sinoatrial node electrical activities. Exp Ther Med 2020; 19:2773-2782. [PMID: 32256760 DOI: 10.3892/etm.2020.8495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 01/09/2020] [Indexed: 01/09/2023] Open
Abstract
Phosphodiesterase (PDE)3-5 are expressed in cardiac tissue and play critical roles in the pathogenesis of heart failure and atrial fibrillation. PDE inhibitors are widely used in the clinic, but their effects on the electrical activity of the heart are not well understood. The aim of the present study was to examine the effects of various PDE inhibitors on spontaneous cardiac activity and compare those effects between sinoatrial nodes (SANs) and pulmonary veins (PVs). Conventional microelectrodes were used to record action potentials in isolated rabbit SAN and PV tissue preparations, before and after administration of different concentrations (0.1, 1 and 10 µM) of milrinone (PDE3 inhibitor), rolipram (PDE4 inhibitor) and sildenafil (PDE5 inhibitor), with or without the application of isoproterenol (cAMP and PKA activator), KT5823 (PKG inhibitor) or H89 (PKA inhibitor). Milrinone (1 and 10 µM) increased the spontaneous activity in PVs by 10.6±4.9 and 16.7±5.3% and in SANs by 9.3±4.3 and 20.7±4.6%, respectively. In addition, milrinone (1 and 10 µM) induced the occurrence of triggered activity (0/8 vs. 5/8; P<0.005) in PVs. Rolipram increased PV spontaneous activity by 7.5±1.3-9.5±4.0%, although this was not significant, and did not alter SAN spontaneous activity. Sildenafil reduced spontaneous activity in PVs to a greater extent than that seen in SANs. Both KT5823 and H89 suppressed milrinone-increased PV spontaneous activity. In the presence of isoproterenol, milrinone did not alter isoproterenol-induced PV arrhythmogenesis, suggesting that the effects of PDE3 are mediated by the protein kinase G and protein kinase A signaling pathways. In conclusion, inhibitors of different PDE subtypes exert diverse electrophysiological effects on PV and SAN activities.
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Affiliation(s)
- Yung-Kuo Lin
- Department of Internal Medicine, Division of Cardiovascular Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 11696, Taiwan, R.O.C.,Department of Internal Medicine, Division of Cardiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11696, Taiwan, R.O.C
| | - Chen-Chuan Cheng
- Division of Cardiology, Chi-Mei Medical Center, Tainan 71004, Taiwan, R.O.C
| | - Jen-Hung Huang
- Department of Internal Medicine, Division of Cardiovascular Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 11696, Taiwan, R.O.C.,Department of Internal Medicine, Division of Cardiology, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11696, Taiwan, R.O.C
| | - Yi-Ann Chen
- Division of Nephrology, Department of Internal Medicine, Sijhih Cathay General Hospital, New Taipei 22174, Taiwan, R.O.C
| | - Yen-Yu Lu
- Division of Cardiology, Department of Internal Medicine, Sijhih Cathay General Hospital, New Taipei 22174, Taiwan, R.O.C
| | - Yao-Chang Chen
- Department of Biomedical Engineering, National Defense Medical Center, Taipei 11490, Taiwan, R.O.C
| | - Shih-Ann Chen
- Heart Rhythm Center and Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei 11217, Taiwan, R.O.C
| | - Yi-Jen Chen
- Department of Internal Medicine, Division of Cardiovascular Medicine, Wan Fang Hospital, Taipei Medical University, Taipei 11696, Taiwan, R.O.C.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei 11696, Taiwan, R.O.C
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4
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Li Z, He Q, Wu C, Chen L, Bi F, Zhou Y, Shan H. Apelin shorten QT interval by inhibiting Kir2.1/I K1 via a PI3K way in acute myocardial infarction. Biochem Biophys Res Commun 2019; 517:272-277. [PMID: 31349969 DOI: 10.1016/j.bbrc.2019.07.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 07/15/2019] [Indexed: 12/24/2022]
Abstract
QT interval prolongation and depolarization of resting membrane potential (RMP) were found in acute myocardial infarction (MI) which is involved in the arrhythmogenic mechanism and raising the risk to initiate torsade de pointes. However, clinical anti-arrhythmic agents that primarily act on QT interval and RMP are not currently available. Our objective was to determine whether Apelin, an endogenous peptide ligand of receptor APJ, affects QT interval and RMP and underlying mechanisms. To test this viewpoint, mice were subjected to MI by ligating the left main coronary artery and Apelin was applied through tail vein at 5 min prior coronary occlusion in tested group. Compared to MI group, pretreatment of Apelin (15 μg/kg) shortened QTc and QT interval induced by MI, significantly elevated RMP and shortened action potential duration (APD) by increased IK1 currents recorded using whole-cell patch technique from cardiomyocytes underwent MI. In cultured neonatal mouse cardiomyocytes, Apelin (1 μmol/L) restored hypoxia-induced Kir2.1 down-regulation, which was abolished by IP3K inhibitor LY-294002. Additionally, Apelin elicited a time-dependent increase in phosphorylation of Akt leading to increase in PI3-kinase activity. These results showed that Apelin enhanced IK1/Kir2.1 currents via IP3K pathway as by rescue ischemia- and hypoxia-induced RMP depolarization and prolongation of QT interval, which may prevent or cure acute ischemic-mediated arrhythmias. This study brings new information to anti-arrhythmic theories and provides a potential target for the clinical management of acute ischemia-related arrhythmias.
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Affiliation(s)
- Zhongrui Li
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China; Department of Ophthalmology, The First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, 150081, China
| | - Qiufu He
- Department of General Practice, The Forth Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, 150081, China
| | - Chengyu Wu
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | | | - Fangfang Bi
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China
| | - Yuhong Zhou
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China.
| | - Hongli Shan
- Department of Pharmacology (the State-Province Key Laboratories of Biomedicine Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, 150081, China.
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5
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Abstract
Novel cardioprotective agents are needed in both heart failure (HF) and myocardial infarction. Increasing evidence from cellular studies and animal models indicate protective effects of phosphodiesterase-5 (PDE5) inhibitors, drugs usually reserved as treatments of erectile dysfunction and pulmonary arterial hypertension. PDE5 inhibitors have been shown to improve contractile function in systolic HF, regress left ventricular hypertrophy, reduce myocardial infarct size and suppress ischaemia-induced ventricular arrhythmias. Underpinning these actions are complex but increasingly understood cellular mechanisms involving the cyclic GMP activation of protein kinase-G in both cardiac myocytes and the vasculature. In clinical trials, PDE5 inhibitors improve symptoms and ventricular function in systolic HF, and accumulating epidemiological data indicate a reduction in cardiovascular events and mortality in PDE5 inhibitor users at high cardiovascular risk. Here, we focus on the translation of underpinning basic science to clinical studies and report that PDE5 inhibitors act through a number of cardioprotective mechanisms, including a direct myocardial action independent of the vasculature. We conclude that future clinical trials should be designed with these mechanisms in mind to identify patient subsets that derive greatest treatment benefit from these novel cardioprotective agents.
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Affiliation(s)
- David Charles Hutchings
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Simon George Anderson
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Jessica L Caldwell
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester Academic Health Science Centre, Manchester, UK
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6
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Kijtawornrat A, Komolvanich S, Saengklub N, Pirintr P, Boonpala P, Buranakarl C. Long-term effect of sildenafil on echocardiographic parameters in dogs with asymptomatic myxomatous mitral valve degeneration. J Vet Med Sci 2017; 79:788-794. [PMID: 28302926 PMCID: PMC5402203 DOI: 10.1292/jvms.16-0372] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Sildenafil is a selective phosphodiesterase-5 inhibitor that has been demonstrated to
delay ventricular remodeling in humans and experimental animals. The aim of this
prospective study was to assess the chronic effects of sildenafil administration on
echocardiographic indices and N-terminal pro-B-type natriuretic peptide (NT-proBNP) in
dogs with naturally occurring, asymptomatic myxomatous mitral valve degeneration. Thirty
client-owned dogs with ACVIM class B1 or B2 were enrolled. Dogs were randomly assigned to
treatment (sildenafil 1–3 mg/kg, PO, BID for 180 days) or control groups. A total of 12
dogs completed the 180 days trial in the sildenafil group, whereas 10 dogs remained in
control group. When comparing the difference from baseline values obtained over time
between groups, the stroke volume (SV) at day 30 was significantly higher in the
sildenafil group (P=0.038). The LA/Ao and the MR jet area were
significantly lower beginning at day 30 (only MR jet area; P=0.006), day
90 (P=0.006 and P=0.027, respectively) and day 180
(P=0.029 and P=0.032, respectively). The 2D-LA was
significantly lower at day 90 when compared with control group (P=0.028).
The differences of NTproBNP from baseline were significantly lower when compared with
control group at the same timepoint (D90, P=0.017 and D180,
P=0.013). In conclusion, this study suggested that long-term treatment
with sildenafil prevented aggravation of disease progression as suggested by several
echocardiographic indices (i.e. SV, LA/Ao, MR jet area, 2D-LA) and reduced NTproBNP level
at the indicated timepoints in dogs with asymptomatic mitral valve degeneration.
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Affiliation(s)
- Anusak Kijtawornrat
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.,Research clusters: Research study and testing of drug's effect related to cardiovascular system in Laboratory Animal, Chulalongkorn University, Bangkok 10330, Thailand
| | - Siripen Komolvanich
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Nakkawee Saengklub
- Department of Physiology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - Prapawadee Pirintr
- Department of Veterinary Biosciences and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand
| | - Pakit Boonpala
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chollada Buranakarl
- Department of Physiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand
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7
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Kayık G, Tüzün NŞ, Durdagi S. Investigation of PDE5/PDE6 and PDE5/PDE11 selective potent tadalafil-like PDE5 inhibitors using combination of molecular modeling approaches, molecular fingerprint-based virtual screening protocols and structure-based pharmacophore development. J Enzyme Inhib Med Chem 2017; 32:311-330. [PMID: 28150511 PMCID: PMC6009860 DOI: 10.1080/14756366.2016.1250756] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The essential biological function of phosphodiesterase (PDE) type enzymes is to regulate the cytoplasmic levels of intracellular second messengers, 3′,5′-cyclic guanosine monophosphate (cGMP) and/or 3′,5′-cyclic adenosine monophosphate (cAMP). PDE targets have 11 isoenzymes. Of these enzymes, PDE5 has attracted a special attention over the years after its recognition as being the target enzyme in treating erectile dysfunction. Due to the amino acid sequence and the secondary structural similarity of PDE6 and PDE11 with the catalytic domain of PDE5, first-generation PDE5 inhibitors (i.e. sildenafil and vardenafil) are also competitive inhibitors of PDE6 and PDE11. Since the major challenge of designing novel PDE5 inhibitors is to decrease their cross-reactivity with PDE6 and PDE11, in this study, we attempt to identify potent tadalafil-like PDE5 inhibitors that have PDE5/PDE6 and PDE5/PDE11 selectivity. For this aim, the similarity-based virtual screening protocol is applied for the “clean drug-like subset of ZINC database” that contains more than 20 million small compounds. Moreover, molecular dynamics (MD) simulations of selected hits complexed with PDE5 and off-targets were performed in order to get insights for structural and dynamical behaviors of the selected molecules as selective PDE5 inhibitors. Since tadalafil blocks hERG1 K channels in concentration dependent manner, the cardiotoxicity prediction of the hit molecules was also tested. Results of this study can be useful for designing of novel, safe and selective PDE5 inhibitors.
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Affiliation(s)
- Gülru Kayık
- a Department of Chemistry , Istanbul Technical University , Istanbul , Turkey.,b Department of Pharmacy , University of Pisa , Pisa , Italy
| | - Nurcan Ş Tüzün
- a Department of Chemistry , Istanbul Technical University , Istanbul , Turkey
| | - Serdar Durdagi
- c Department of Biophysics , School of Medicine, Bahcesehir University , Istanbul , Turkey
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8
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Sube R, Ertel EA. Cardiomyocytes Derived from Human Induced Pluripotent Stem Cells: An In-Vitro Model to Predict Cardiac Effects of Drugs. ACTA ACUST UNITED AC 2017. [DOI: 10.4236/jbise.2017.1011040] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Kayık G, Tüzün NŞ, Durdagi S. In silico design of novel hERG-neutral sildenafil-like PDE5 inhibitors. J Biomol Struct Dyn 2016; 35:2830-2852. [PMID: 27581752 DOI: 10.1080/07391102.2016.1231634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Cyclic nucleotide phosphodiesterase enzymes (PDEs) have functions in regulating the levels of intracellular second messengers, 3', 5'-cyclic adenosine monophosphate (cAMP) and 3', 5'-cyclic guanosine monophosphate (cGMP), via hydrolysis and decomposing mechanisms in cells. They take essential roles in modulating various cellular activities such as memory and smooth muscle functions. PDE type 5 (PDE5) inhibitors enhance the vasodilatory effects of cGMP in the corpus cavernosum and they are used to treat erectile dysfunction. Patch clamp experiments showed that the IC50 values of the human ether-à-go-go-related gene (hERG1) potassium (K) ion channel blocking affinity of PDE5 inhibitors sildenafil, vardenafil, and tadalafil as 33, 12, and 100 μM, respectively. hERG1 channel is responsible for the regulation of the action potential of human ventricular myocyte by contributing the rapid component of delayed rectifier K+ current (IKr) component of the cardiac action potential. In this work, interaction patterns and binding affinity predictions of selected PDE5 inhibitors against the hERG1 channel are studied. It is attempted to develop PDE5 inhibitor analogs with lower binding affinity to hERG1 ion channel while keeping their pharmacological activity against their principal target PDE5 using in silico methods. Based on detailed analyses of docking poses and predicted interaction energies, novel analogs of PDE5 inhibitors with lower predicted binding affinity to hERG1 channels without loosing their principal target activity were proposed. Moreover, molecular dynamics (MD) simulations and post-processing MD analyses (i.e. Molecular Mechanics/Generalized Born Surface Area calculations) were performed. Detailed analysis of molecular simulations helped us to better understand the PDE5 inhibitor-target binding interactions in the atomic level. Results of this study can be useful for designing of novel and safe PDE5 inhibitors with enhanced activity and other tailored properties.
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Affiliation(s)
- Gülru Kayık
- a Department of Chemistry , Istanbul Technical University , Istanbul 34469 , Turkey
| | - Nurcan Ş Tüzün
- a Department of Chemistry , Istanbul Technical University , Istanbul 34469 , Turkey
| | - Serdar Durdagi
- b Department of Biophysics , School of Medicine, Bahcesehir University , Istanbul , Turkey
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10
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Computational investigations of hERG channel blockers: New insights and current predictive models. Adv Drug Deliv Rev 2015; 86:72-82. [PMID: 25770776 DOI: 10.1016/j.addr.2015.03.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 01/13/2015] [Accepted: 03/04/2015] [Indexed: 01/08/2023]
Abstract
Identification of potential human Ether-a-go-go Related-Gene (hERG) potassium channel blockers is an essential part of the drug development and drug safety process in pharmaceutical industries or academic drug discovery centers, as they may lead to drug-induced QT prolongation, arrhythmia and Torsade de Pointes. Recent reports also suggest starting to address such issues at the hit selection stage. In order to prioritize molecules during the early drug discovery phase and to reduce the risk of drug attrition due to cardiotoxicity during pre-clinical and clinical stages, computational approaches have been developed to predict the potential hERG blockage of new drug candidates. In this review, we will describe the current in silico methods developed and applied to predict and to understand the mechanism of actions of hERG blockers, including ligand-based and structure-based approaches. We then discuss ongoing research on other ion channels and hERG polymorphism susceptible to be involved in LQTS and how systemic approaches can help in the drug safety decision.
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11
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Coi A, Bianucci AM. Combining structure- and ligand-based approaches for studies of interactions between different conformations of the hERG K+ channel pore and known ligands. J Mol Graph Model 2013; 46:93-104. [PMID: 24185260 DOI: 10.1016/j.jmgm.2013.10.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 10/01/2013] [Accepted: 10/03/2013] [Indexed: 11/13/2022]
Abstract
Drug-induced insurgence of cardiotoxic effects signaled by the prolongation of the QT interval in the electrocardiogram, has the potential to evolve into a characteristic arrhythmic event named Torsade de Pointes (TdP). Although several different mechanisms can theoretically lead to prolonged QT interval, most of drugs showing this side effect, prolong the cardiac repolarization time through the inhibition of the rapid component of the delayed repolarizing current (IKr) which in humans is carried by a K(+) channel protein encoded by hERG. In this study, four 3D-models, representing different conformational states of hERG K(+) channel, were built by a homology-based technique. A dataset of 59 compounds was collected from the literature and rationally selected according to the availability of IC50 values derived from whole-cell patch clamp performed at 37 °C on HEK cells. Molecular docking was carried out on each one of the four conformations of the channel, hundreds of docking-based molecular descriptors were obtained and used, together with other 2D and 3D molecular descriptors, to develop QSAR models. The statistical parameters describing the accordance between predicted and experimental data and the interpretation of the QSAR models enabled us to assess the reliability of the four 3D-models of the channel pore, thus allowing to look in more depth at binding modes and key features of the interactions occurring between the hERG K(+) channel and ligands endowed of blocking activity.
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Affiliation(s)
- Alessio Coi
- INSTM (Consorzio National Interuniversity Consortium of Materials Science and Technology), Via Giusti 9, 50121 Firenze, Italy
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12
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Varma A, Shah KB, Hess ML. Phosphodiesterase inhibitors, congestive heart failure, and sudden death: time for re-evaluation. ACTA ACUST UNITED AC 2012; 18:229-33. [PMID: 22507298 DOI: 10.1111/j.1751-7133.2012.00293.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A 42-year-old diabetic man was admitted with systolic heart failure and pulmonary hypertension being treated with sildenafil for the previous year. With an increase in creatinine, he experienced 3 episodes of ventricular tachycardia and ventricular fibrillation. Withdrawal of the phosphodiesterase (PDE) inhibitor resulted in no further episodes of dysrhythmias. The basic pharmacology of PDE inhibitors is presented and the use of PDE-3 inhibitors for the treatment of heart failure causing an increase in sudden death is also reviewed. There have been several cases of sudden death associated with sildenafil use and with its increasing use in patients with severe pulmonary hypertension and decompensated heart failure. The authors also reviewed the electrophysiologic effects of PDE-5 inhibitors associated with their use. The crossover between PDE-3 and PDE-5 inhibitors is also discussed and caution is urged when contemplating the use of PDE-5 inhibitors in patients with systolic heart failure and pulmonary hypertension.
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Affiliation(s)
- Amit Varma
- Department of Internal Medicine/Cardiology, CHF and Heart Transplant, Virginia Commonwealth University Health System, Richmond, VA 23298, USA
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13
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Does your model weigh the same as a duck? J Comput Aided Mol Des 2011; 26:57-67. [PMID: 22187141 DOI: 10.1007/s10822-011-9530-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2011] [Accepted: 12/10/2011] [Indexed: 10/14/2022]
Abstract
Computer-aided drug design is a mature field by some measures, and it has produced notable successes that underpin the study of interactions between small molecules and living systems. However, unlike a truly mature field, fallacies of logic lie at the heart of the arguments in support of major lines of research on methodology and validation thereof. Two particularly pernicious ones are cum hoc ergo propter hoc (with this, therefore because of this) and confirmation bias (seeking evidence that is confirmatory of the hypothesis at hand). These fallacies will be discussed in the context of off-target predictive modeling, QSAR, molecular similarity computations, and docking. Examples will be shown that avoid these problems.
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14
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The Use of Beat-to-Beat Electrocardiogram Analysis to Distinguish QT/QTc Interval Changes Caused by Moxifloxacin From Those Caused by Vardenafil. Clin Pharmacol Ther 2011; 90:449-54. [DOI: 10.1038/clpt.2011.139] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Tan Y, Chen Y, You Q, Sun H, Li M. Predicting the potency of hERG K+ channel inhibition by combining 3D-QSAR pharmacophore and 2D-QSAR models. J Mol Model 2011; 18:1023-36. [DOI: 10.1007/s00894-011-1136-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2011] [Accepted: 05/23/2011] [Indexed: 02/06/2023]
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Jang JW, Song CM, Choi KH, Cho YS, Baek DJ, Shin KJ, Pae AN. In silico Analysis on hERG Channel Blocking Effect of a Series of T-type Calcium Channel Blockers. B KOREAN CHEM SOC 2011. [DOI: 10.5012/bkcs.2011.32.1.251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Coi A, Massarelli I, Saraceno M, Carli N, Testai L, Calderone V, Bianucci AM. Quantitative Structure-Activity Relationship Models for Predicting Biological Properties, Developed by Combining Structure- and Ligand-Based Approaches: An Application to the Human Ether-a-go-go-Related Gene Potassium Channel Inhibition. Chem Biol Drug Des 2009; 74:416-33. [DOI: 10.1111/j.1747-0285.2009.00873.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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18
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Polak S, Wiśniowska B, Brandys J. Collation, assessment and analysis of literature in vitro data on hERG receptor blocking potency for subsequent modeling of drugs' cardiotoxic properties. J Appl Toxicol 2009; 29:183-206. [PMID: 18988205 DOI: 10.1002/jat.1395] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The assessment of the torsadogenic potency of a new chemical entity is a crucial issue during lead optimization and the drug development process. It is required by the regulatory agencies during the registration process. In recent years, there has been a considerable interest in developing in silico models, which allow prediction of drug-hERG channel interaction at the early stage of a drug development process. The main mechanism underlying an acquired QT syndrome and a potentially fatal arrhythmia called torsades de pointes is the inhibition of potassium channel encoded by hERG (the human ether-a-go-go-related gene). The concentration producing half-maximal block of the hERG potassium current (IC(50)) is a surrogate marker for proarrhythmic properties of compounds and is considered a test for cardiac safety of drugs or drug candidates. The IC(50) values, obtained from data collected during electrophysiological studies, are highly dependent on experimental conditions (i.e. model, temperature, voltage protocol). For the in silico models' quality and performance, the data quality and consistency is a crucial issue. Therefore the main objective of our work was to collect and assess the hERG IC(50) data available in accessible scientific literature to provide a high-quality data set for further studies.
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Affiliation(s)
- Sebastian Polak
- Toxicology Department, Faculty of Pharmacy, Medical Collage, Jagiellonian University, Poland.
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Coi A, Massarelli I, Testai L, Calderone V, Bianucci AM. Identification of “toxicophoric” features for predicting drug-induced QT interval prolongation. Eur J Med Chem 2008; 43:2479-88. [DOI: 10.1016/j.ejmech.2007.12.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Revised: 12/07/2007] [Accepted: 12/11/2007] [Indexed: 11/26/2022]
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20
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Smits JPP, Blom MT, Wilde AAM, Tan HL. Cardiac sodium channels and inherited electrophysiologic disorders: a pharmacogenetic overview. Expert Opin Pharmacother 2008; 9:537-49. [DOI: 10.1517/14656566.9.4.537] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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21
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Doggrell S. Do vardenafil and tadalafil have advantages over sildenafil in the treatment of erectile dysfunction? Int J Impot Res 2006; 19:281-95. [PMID: 17183346 DOI: 10.1038/sj.ijir.3901525] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Erectile dysfunction (ED) affects up to 50% of men between the ages of 40 and 70 years of age. Sildenafil, vardenafil and tadalafil have all been shown to be similarly effective in the treatment of men with ED of vary etiologies, to have similar adverse effects profiles, and to improve quality-of-life by similar amounts. As these phosphodiesterase 5 (PDE5) inhibitors all increase the hypotensive effects of nitrates, they are not suitable for use in patients taking nitrates for the treatment of ischaemic heart disease. All three inhibitors must be used with caution in patients taking alpha(1)-adrenoceptors antagonists for benign prostatic hyperplasia. Although nonarteritic anterior ischaemic neuropathy has been reported in some users of the PDE5 inhibitors, there is no conclusive evidence that PDE5 inhibitors cause this rare effect. Tadalafil has a longer half-life than sildenafil or vardenafil, and a longer duration of action than sildenafil and vardenafil. Most preference studies have shown tadalafil to be preferred, but there are serious limitations to some of these studies. One approach to treatment is to give each patient a short- and long-acting agent, and for individuals to decide their preference.
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Affiliation(s)
- S Doggrell
- School of Science, Charles Darwin University, Casuarina, Northern Territory, Australia.
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22
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Jackson G, Montorsi P, Cheitlin MD. Cardiovascular safety of sildenafil citrate (Viagra®): An updated perspective. Urology 2006; 68:47-60. [PMID: 17011375 DOI: 10.1016/j.urology.2006.05.047] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Revised: 04/25/2006] [Accepted: 05/22/2006] [Indexed: 11/18/2022]
Abstract
Sildenafil citrate (Viagra; Pfizer Inc, New York, NY) relaxes vascular smooth muscle, resulting in modest reductions in blood pressure that are insufficient to stimulate a reflex increase in heart rate. These blood pressure reductions are similar for healthy men and men with coronary artery disease (CAD) or who use antihypertensive drugs. Sildenafil does not affect the force of cardiac contraction, and cardiac performance is unaffected. Sildenafil is mildly vasodilating in the coronary circulation and does not increase the risk of ventricular arrhythmia. During exercise and recovery, sildenafil does not cause clinically significant alterations in hemodynamic parameters in men with CAD, and it has no negative effects on coronary oxygen consumption, ischemia, or exercise capacity. Clinical trial data from >13,000 patients, 7 years of international postmarketing data, and observational studies of >28,000 men in the United Kingdom and 3813 men in the European Union reveal that (1) there are no special cardiovascular concerns when sildenafil is used in accordance with product labeling and (2) the risk for serious events such as myocardial infarction or death is not increased. However, because safety has not been established in patients with recent serious cardiovascular events, hypotension or uncontrolled hypertension, or retinitis pigmentosa, physicians should consult their current local prescribing information before prescribing sildenafil for these patients. Among men with erectile dysfunction treated with sildenafil, the adverse event profile is similar overall to that in men with comorbid cardiovascular disease (CVD), it is similar between those with and without CAD, and it is similar between those who take and those who do not take antihypertensive drugs (regardless of the number or class). In a controlled interaction study of sildenafil and amlodipine, the mean additional reduction in supine blood pressure was 8 mm Hg systolic and 7 mm Hg diastolic. Sildenafil should be used with caution in patients who take alpha-blockers because coadministration may lead to symptomatic hypotension in some individuals. When sildenafil is coadministered with an alpha-blocker, patients should be stable on alpha-blocker therapy before initiating sildenafil treatment and sildenafil should be initiated at the lowest dose. Also, in the absence of information specific to mixed alpha/beta blockers, such as carvedilol and labetalol, similar care should be taken as for alpha-blockers. Sildenafil potentiates the hypotensive effects of nitrates, and its administration to patients who are using organic nitrates in any form, either regularly or intermittently, is contraindicated. Before prescribing sildenafil, physicians should carefully consider whether their patients with underlying CVD could be affected adversely by resuming sexual activity. Management recommendations based on cardiovascular risk, from the Second Princeton Consensus Conference, are presented.
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Seierstad M, Agrafiotis DK. A QSAR Model of hERG Binding Using a Large, Diverse, and Internally Consistent Training Set. Chem Biol Drug Des 2006; 67:284-96. [PMID: 16629826 DOI: 10.1111/j.1747-0285.2006.00379.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Over the past decade, the pharmaceutical industry has begun to address an addition to ADME/Tox profiling--the ability of a compound to bind to and inhibit the human ether-a-go-go-related gene (hERG)-encoded cardiac potassium channel. With the compilation of a large and diverse set of compounds measured in a single, consistent hERG channel inhibition assay, we recognized a unique opportunity to attempt to construct predictive QSAR models. Early efforts with classification models built from this training set were very encouraging. Here, we report a systematic evaluation of regression models based on neural network ensembles in conjunction with a variety of structure representations and feature selection algorithms. The combination of these modeling techniques (neural networks to capture non-linear relationships in the data, feature selection to prevent over-fitting, and aggregation to minimize model instability) was found to produce models with very good internal cross-validation statistics and good predictivity on external data.
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Affiliation(s)
- Mark Seierstad
- Johnson & Johnson Pharmaceutical Research & Development, L.L.C., 3210 Merryfield Row, San Diego, CA 92121, USA.
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24
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Yunomae K, Ichisaki S, Matsuo J, Nagayama S, Fukuzaki K, Nagata R, Kito G. Effects of phosphodiesterase (PDE) inhibitors on human ether-a-go-go related gene (hERG) channel activity. J Appl Toxicol 2006; 27:78-85. [PMID: 17146843 DOI: 10.1002/jat.1201] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
It is presumed that phosphodiesterase (PDE) inhibitors have two mechanisms for inhibition of hERG currents in the acute applications to cells: direct channel block, and downregulation of human ether-a-go-go related gene (hERG) activities by PKA-dependent pathway mediated phosphorylation through their inhibitory effects against PDE enzymes. However, it is unknown whether PDE inhibition contributes to the inhibitory effects of PDE inhibitors on hERG currents. This study examined the effects of various PDE inhibitors on hERG currents using both the whole-cell and perforated patch-clamp techniques in hERG transfected CHO-K1 cells. The study also investigated the contribution of the PKA-dependent pathway to the inhibitory effects of PDE inhibitors on hERG currents. Of the PDE inhibitors tested, vinpocetine, erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA), vesnarinone, rolipram and dipyridamole decreased hERG currents in a concentration-dependent manner. Vinpocetine and vesnarinone markedly decreased the hERG current with an IC (50)of 0.13 and 20.6 microm, respectively, at comparatively low concentrations. Furthermore, vinpocetine caused a cumulative block of hERG currents. Milrinone, amrinone and zaprinast had no effect on the hERG current up to 100 microm. Of the PDE3 inhibitors (vesnarinone, amrinone and milrinone), only vesnarinone showed an hERG inhibitory effect. The inhibitory effects of vinpocetine and vesnarinone were not significantly affected by the co-application of protein kinase inhibitors. Furthermore, the protein kinase activators had no effect on hERG currents. It is concluded that vinpocetine and vesnarinone block the hERG channel directly, and that the inhibitory effect on intracellular PDE in the PKA-dependent pathway may not be involved in the inhibition of hERG currents in hERG transfected CHO-K1 cells.
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Affiliation(s)
- Kiyokazu Yunomae
- Shin Nippon Biomedical Laboratories Ltd, Drug Safety Research Laboratories, 2438 Miyanoura, Kagoshima 891-1394, Japan.
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25
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Carosa E, Lombardo F, Martini P, Brandetti F, Jannini EA. The therapeutic dilemma: How to use tadalafil. ACTA ACUST UNITED AC 2005; 28 Suppl 2:74-80. [PMID: 16236070 DOI: 10.1111/j.1365-2605.2005.00590.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tadalafil, a type 5 phosphodiesterase inhibitor, is a new and effective therapy for erectile dysfunction. It has unique pharmacokinetic properties in its drug class, which also includes sildenafil and vardenafil. It is also well tolerated with few side-effects, and can be used in difficult patients such as neuropaths or diabetics.
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Affiliation(s)
- E Carosa
- Course of Endocrinology and Medical Sexology, Department of Experimental Medicine, University of L'Aquila 67100 L'Aquila, Italy
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26
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Beasley CM, Mitchell MI, Dmitrienko AA, Emmick JT, Shen W, Costigan TM, Bedding AW, Turik MA, Bakhtyari A, Warner MR, Ruskin JN, Cantilena LR, Kloner RA. The Combined Use of Ibutilide as an Active Control With Intensive Electrocardiographic Sampling and Signal Averaging as a Sensitive Method to Assess the Effects of Tadalafil on the Human QT Interval. J Am Coll Cardiol 2005; 46:678-87. [PMID: 16098435 DOI: 10.1016/j.jacc.2005.05.036] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2004] [Revised: 04/28/2005] [Accepted: 05/03/2005] [Indexed: 01/10/2023]
Abstract
OBJECTIVES This study was designed to evaluate effects of tadalafil, a phosphodiesterase-5 inhibitor used for the treatment of erectile dysfunction (ED), on the QT interval. BACKGROUND Cardiovascular disease is common in men with ED. Men with cardiovascular disease and ED may have decreased cardiac repolarization reserve. METHODS Effects of tadalafil (100 mg by mouth), ibutilide (0.002 mg/kg intravenously), and placebo on the QT interval in healthy men were compared (placebo and tadalafil [n = 90], with a subset [n = 61] receiving all treatments; mean age 30 years, range 18 to 53 years). Electrocardiographic sampling was done for two days before treatment and on treatment days. The QT was corrected for RR interval with five correction methods, including an individual correction (QTcI). Plasma concentrations of tadalafil were measured to evaluate concentration-QT effect relationships. RESULTS At the time corresponding to maximum plasma concentration of tadalafil, the mean difference in the change in QTcI between tadalafil and placebo was 2.8 ms; tadalafil was equivalent to placebo (a priori, upper limit of 90% confidence interval < 10 ms [actual = 4.4 ms]; post hoc, upper limit of 95% confidence interval < 5 ms [actual = 4.8]). The active control, ibutilide, significantly increased QTcI by 6.9 and 8.9 ms compared with tadalafil and placebo, respectively. Similar statistical results were obtained with four additional QT correction methods. No subject had a QTcI > or = 450 ms or an increase in QTcI > or = 30 ms with any treatment. CONCLUSIONS Based on the a priori statistical test of equivalence, placebo and high-dose tadalafil produced equivalent effects on the QT interval. This study reliably discerned 5- to 10-ms changes in corrected QT in the ibutilide active control group.
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Seftel AD, Farber J, Fletcher J, Deeley MC, Elion-Mboussa A, Hoover A, Yu A, Fredlund P. A three-part study to investigate the incidence and potential etiologies of tadalafil-associated back pain or myalgia. Int J Impot Res 2005; 17:455-61. [PMID: 16034469 DOI: 10.1038/sj.ijir.3901374] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The potential mechanisms underlying back pain and/or myalgia experienced by men taking tadalafil were investigated. An integrated analysis of 10 placebo-controlled tadalafil clinical trials (N=1846) showed that the incidence of back pain and/or myalgia was 9.4% in patients receiving tadalafil 10 mg (N=394), 8.3% in patients receiving tadalafil 20 mg (N=883) and 3.7% in placebo-treated patients (N=569). One (0.3%) patient receiving tadalafil 10 mg, six (0.7%) patients receiving tadalafil 20 mg, and no patients receiving placebo discontinued treatment due to back pain and/or myalgia. In a prospective study in healthy volunteers, no substantial changes were observed in laboratory markers indicative of inflammation or muscle damage, and tadalafil did not affect renal plasma flow nor produce lumbar or gluteal myositis by positron emission tomography scan or magnetic resonance imaging. Although the mechanism of back pain and/or myalgia remains unknown, these events appear to be self-limiting and a general effect of phosphodiesterase 5 inhibition.
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Affiliation(s)
- A D Seftel
- Case Western Reserve University, University Hospitals of Cleveland, Cleveland, OH 44106-5046, USA.
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