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Hagiwara-Nagasawa M, Kambayashi R, Goto A, Nunoi Y, Izumi-Nakaseko H, Takei Y, Matsumoto A, Sugiyama A. Cardiohemodynamic and Arrhythmogenic Effects of the Anti-Atrial Fibrillatory Compound Vanoxerine in Halothane-Anesthetized Dogs. Cardiovasc Toxicol 2020; 21:206-215. [PMID: 33074476 DOI: 10.1007/s12012-020-09612-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Accepted: 10/10/2020] [Indexed: 11/27/2022]
Abstract
While vanoxerine (GBR-12909) is a synaptosomal dopamine uptake inhibitor, it also suppresses IKr, INa and ICa,L in vitro. Based on these profiles on ionic currents, vanoxerine has been developed as a candidate compound for treating atrial fibrillation. To investigate electropharmacological profiles, vanoxerine dihydrochloride was intravenously administered at 0.03 and 0.3 mg/kg to halothane-anesthetized dogs (n = 4), possibly providing subtherapeutic and therapeutic concentrations, respectively. The low dose increased the heart rate and cardiac output, whereas it prolonged the ventricular refractoriness. The high dose decreased the heart rate but increased the total peripheral vascular resistance, whereas it delayed the ventricular repolarization and increased the atrial refractoriness in addition to further enhancing the ventricular refractoriness. The extent of increase in the refractoriness in the atrium was 0.8 times of that in the ventricle. The high dose also prolonged the early and late repolarization periods of the ventricle as well as the terminal repolarization period. Meanwhile, no significant change was detected in the mean blood pressure, ventricular contraction, preload to the left ventricle, or the intra-atrial, intra-ventricular or atrioventricular conductions. The high dose can be considered to inhibit IKr, but it may not suppress INa or ICa in the in situ heart, partly explaining its poor atrial selectivity for increasing refractoriness. The prolongation of early repolarization period may reflect enhancement of net inward current, providing potential risk for intracellular Ca2+ overload. Thus, vanoxerine may provide both trigger and substrate toward torsade de pointes, which would make the drug less promising as an anti-atrial fibrillatory drug.
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Affiliation(s)
- Mihoko Hagiwara-Nagasawa
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Ryuichi Kambayashi
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Ai Goto
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Yoshio Nunoi
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Hiroko Izumi-Nakaseko
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Yoshinori Takei
- Faculty of Medicine, Department of Translational Research & Cellular Therapeutics, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Akio Matsumoto
- Faculty of Medicine, Department of Aging Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan
| | - Atsushi Sugiyama
- Faculty of Medicine, Department of Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan.
- Faculty of Medicine, Department of Translational Research & Cellular Therapeutics, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan.
- Faculty of Medicine, Department of Aging Pharmacology, Toho University, 5-21-16 Omori-nishi, Ota-ku, Tokyo, 143-8540, Japan.
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Frommeyer G, Eckardt L. Drug-induced proarrhythmia: risk factors and electrophysiological mechanisms. Nat Rev Cardiol 2015; 13:36-47. [PMID: 26194552 DOI: 10.1038/nrcardio.2015.110] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Drug-induced ventricular tachyarrhythmias can be caused by cardiovascular drugs, noncardiovascular drugs, and even nonprescription agents. They can result in arrhythmic emergencies and sudden cardiac death. If a new arrhythmia or aggravation of an existing arrhythmia develops during therapy with a drug at a concentration usually considered not to be toxic, the situation can be defined as proarrhythmia. Various cardiovascular and noncardiovascular drugs can increase the occurrence of polymorphic ventricular tachycardia of the 'torsade de pointes' type. Antiarrhythmic drugs, antimicrobial agents, and antipsychotic and antidepressant drugs are the most important groups. Age, female sex, and structural heart disease are important risk factors for the occurrence of torsade de pointes. Genetic predisposition and individual pharmacodynamic and pharmacokinetic sensitivity also have important roles in the generation of arrhythmias. An increase in spatial or temporal dispersion of repolarization and a triangular action-potential configuration have been identified as crucial predictors of proarrhythmia in experimental models. These studies emphasized that sole consideration of the QT interval is not sufficient to assess the proarrhythmic risk. In this Review, we focus on important triggers of proarrhythmia and the underlying electrophysiological mechanisms that can enhance or prevent the development of torsade de pointes.
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Affiliation(s)
- Gerrit Frommeyer
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
| | - Lars Eckardt
- Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Albert-Schweitzer Strasse 33, D-48149 Münster, Germany
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Sun F, Su Z, Sui C, Zhang C, Yuan L, Meng Q, Teng L, Li Y. Studies on the Acute Toxicity, Pharmacokinetics and Pharmacodynamics of Paliperidone Derivatives - Comparison to Paliperidone and Risperidone in Mice and Rats. Basic Clin Pharmacol Toxicol 2010; 107:656-62. [DOI: 10.1111/j.1742-7843.2010.00552.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Abstract
Risperidone has been reported as a well-tolerated antipsychotic in children. The most common side effects of risperidone are anxiety, headaches, insomnia, and agitation, which frequently appear with high doses. Although it is known that risperidone affects the cardiac conduction system, symptomatic bradycardia has not been reported previously in children. We report a child who developed syncope because of sinus arrest with long pauses (>3 seconds) with therapeutic doses of risperidone. This case suggests that close monitoring is mandatory even during therapeutic treatment with risperidone.
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Yokoyama H, Nakamura Y, Iwasaki H, Nagayama Y, Hoshiai K, Mitsumori Y, Sugiyama A. Effects of Acute Intravenous Administration of Pentamidine, a Typical hERG-Trafficking Inhibitor, on the Cardiac Repolarization Process of Halothane-Anesthetized Dogs. J Pharmacol Sci 2009; 110:476-82. [DOI: 10.1254/jphs.09071fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Ishizaka T, Takahara A, Iwasaki H, Mitsumori Y, Kise H, Nakamura Y, Sugiyama A. Comparison of electropharmacological effects of bepridil and sotalol in halothane-anesthetized dogs. Circ J 2008; 72:1003-11. [PMID: 18503230 DOI: 10.1253/circj.72.1003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Bepridil is known to have a multiple ion channel-blocking property in the heart, which has been applied for the treatment of atrial fibrillation and drug-refractory ventricular tachyarrhythmias. In this study, the electro-pharmacological effects of bepridil were compared with those of dl-sotalol, a representative class III antiarrhythmic drug, using the halothane-anesthetized canine model. METHODS AND RESULTS Cardiovascular and electrophysiological variables were measured under the halothane anesthesia. Intravenous administration of bepridil (0.3 mg/kg, n=4) delayed the intraventricular conduction and prolonged the ventricular effective refractory period, whereas dl-sotalol (0.3 mg/kg, iv, n=4) inhibited atrioventricular conduction and prolonged the atrial and ventricular effective refractory period. The additional administration of 10 times the higher dose of bepridil or dl-sotalol (ie, 3 mg/kg, iv, n=4 for each group) decreased blood pressure, suppressed ventricular contraction and sinus automaticity, and prolonged the atrial and ventricular effective refractory period and monophasic action potential duration, in addition to the effects of the low dose. CONCLUSIONS The electropharmacological effects of bepridil and dl-sotalol were similar, although their potency for each cardiovascular variable varied significantly. These findings can be useful when selecting these drugs according to the pathophysiological condition of a patient.
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Affiliation(s)
- Tomomichi Ishizaka
- Department of Pharmacology, Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Chuo, Japan
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Sensitive and reliable proarrhythmia in vivo animal models for predicting drug-induced torsades de pointes in patients with remodelled hearts. Br J Pharmacol 2008; 154:1528-37. [PMID: 18552873 DOI: 10.1038/bjp.2008.240] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
As an increasing number of non-cardiac drugs have been reported to cause QT interval prolongation and torsades de pointes (TdP), we extensively studied the utility of atrioventricular (AV) block animals as a model to predict their torsadogenic action in human. The present review highlights such in vivo proarrhythmia models. In the case of the canine model, test substances were administered p.o. at conscious state >4 weeks after the induction of AV block, with subsequent Holter ECG monitoring to evaluate drug effects. Control AV block dogs (no pharmacological treatment) survive for several years without TdP attack. For pharmacologically treated dogs, drugs were identified as high, low or no risk. High-risk drugs induced TdP at 1-3 times the therapeutic dose. Low-risk drugs did not induce TdP at this dose range, but induced it at higher doses. No-risk drugs never induced TdP at any dose tested. Electrophysiological, anatomical histological and biochemical adaptations against persistent bradycardia-induced chronic heart failure were observed in AV block dogs. Recently, we have developed another highly sensitive proarrhythmia model using a chronic AV block cynomolgus monkey, which possesses essentially the same pathophysiological adaptations and drug responses as those demonstrated in the canine model. As a common remodelling process leading to a diminished repolarization reserve may present in patients who experience drug-induced TdP and in the AV block animals, the in vivo proarrhythmia models described in this review may be useful for predicting the risk of pharmacologically induced TdP in humans.
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Abstract
Children with learning disabilities can present numerous challenges in the acute hospital setting. This review article examines the causes and presentations of learning disability, and considers some of the management strategies employed when these children present for surgery.
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