ABC | Volume 114, Nº6, June 2020

Viewpoint Wu et al. Preventing Torsades de Pointes during Hydroxychloroquine/Azithromycin Treatment Arq Bras Cardiol. 2020; 114(6):1061-1066 - Maintain K + > 4.0 - Maintain Mg ++ > 2.0 - Avoid hypocalcemia N.B.: Even in patients with normal blood level, it is recommended to maintain empirical magnesium supplementation orally, except in those with renal failure (ClCr < 30 ml/min). Regarding electrolyte control during patient progression: Electrolyte monitoring routine should be determined at clinical discretion, whenever adjustments are needed to maintain ideal or desirable levels during treatment, especially in patients with an initial QTc interval > 470ms. Regarding use of concomitant medications: It is necessary to avoid prescribing other non-essential drugs that prolong the QT interval. Numerous drugs that are commonly used in hospitalized patients can block the hERG channel, prolong ventricular repolarization time, and facilitate the occurrence of TdP. 18 It is important to supervise use of medication whenever possible in order to guarantee patient safety. Table 2 provides lists of low risk (green), possible risk (orange), and high risk (red) medications with respect to prolongation of the QT interval and occurrence of TdP. Therefore, whenever possible, additional low-risk medications should be preferred, as both HCQ and AZ are already listed as high risk for the occurrence of TdP. Some medications can increase risk through other mechanisms or indirectly, as is the case of hypokalemia induced by diuretics. The complete list of drug interactions should be checked daily by the website crediblemeds.org. 19 In the event of ventricular arrhythmia or TdP (Table 3): 20,21 - Lidocaine is the antiarrhythmic drug of choice: - Magnesium sulfate - Isoprotenerol for TdP mediated by bradycardia - Provisional pacemaker for bradycardic patients with recurrent TdP. Initial heart rate should be programmed to 90 bpm and adjustments should be made according to patient’s clinical response. - Immediately suspend the use of all medications with potential to prolong the QT interval. Conclusion The risk of fatal arrhythmias, increased with the use of HCQ and/or AZ, in patients with COVID-19, or in other daily situations, outside the pandemic, with medications that may potentially prolong the QT interval, can be minimized with the application of conduct protocols that help healthcare professionals decide on prescription and maintenance of treatment. Table 2 – List of medications to avoid (red and orange) High risk Moderate risk Low risk or NC Antiarrhythmic drugs Amiodarone Sotalol Propafenone Lidocaine Propranolol Magnesium sulfate Isoproterenol Antipsychotic drugs Haloperidol Risperidone Benzodiazepine Chlorpromazine Quetiapine Levomepromazine Promethazine Olanzapine Sedatives Propofol Dexmedetomidine Midazolam Fentanyl Antiemetic and prokinetic drugs Ondansentron Domperidone Bromopride Cisapride Cimetidine Granisetrone Metoclopramide Dimenhydrinate Antibiotics Quinolones Piperacillin/ tazobactam Sulfamethoxazole/ trimethoprim Teicoplanin Vancomycin Antifungal drugs Fluconazol Anfotericina Itraconazol Voriconazol Proton pump inhibitors Pantoprazol Omeprazol Esomeprazol Lanzoprazol Antiallergic drugs Promethazine Fexofenadine Hydroxyzine Diphenhydramine Loratadine Pandemic Chloroquine Azithromycin Oseltamivir Bronchodilators Salbutamol Fenoterol Formoterol Terbutalina Anticholinesterase drugs Donepezil Galantamine Antidepressives Citalopram Escitalopram Fluoxetine Paroxetine Mirtazapine Tricyclics Sertraline Venlafaxine Others Cilostazol Methadone Tramadol Loperamide Phenytoin Special precautions Diuretics Precaution with spoliation of electrolytes NC – Not classified, i.e., absence of evidence of prolonged QT interval based on published studies. Author contributions Conception and design of the research and Data acquisition: Wu TC; Writing of the manuscript: Wu TC, Sacilotto L, Darrieux FCC, Pisani CF, Hachul DT; Critical 1065