Torsade de Pointes Induced by Hypokalemia from Imipenem and Piperacillin

Incidence and Determinants of Piperacillin/Tazobactam-Associated Hypokalemia: A Retrospective Study

Piperacillin/tazobactam (TZP) is a commonly used antibiotic for treating moderate-to-severe infections because of its broad-spectrum activity and recommendation as an alternative to carbapenem. TZP-associated severe hypokalemia has been consistently reported; however, related studies are very rare. This study aimed to evaluate the incidence and risk factors of TZP-associated hypokalemia (TAH). A retrospective cohort study was conducted on hospitalized adult patients who received TZP from 1 January 2015 to 31 December 2017 at a tertiary teaching hospital. Of the 713 patients, 13.9% had TAH. As a result of multivariate logistic regression analysis, older age (OR 1.03, 95% CI: 1.02−1.05, p < 0.001), female sex (OR 1.88, 95% CI: 1.18−3.00, p = 0.008), longer duration of TZP therapy (OR 1.08, 95% CI: 1.04−1.13, p < 0.001), and higher TZP daily dose (OR 1.10, 95% CI: 1.01−1.20, p = 0.049) were independently associated with TAH. In contrast, higher baseline serum potassium level (OR 0.13, 95% CI: 0.07−0.26, p < 0.001) was related to lower TAH. Furthermore, hypokalemia mostly occurred in the early days of TZP therapy (median onset time: 4 days). Thus, close monitoring of serum potassium levels, especially upon therapy initiation, is essential to prevent TAH.

Polymorphic Ventricular Tachycardia with a Normal QTc Interval in a Patient with COVID-19 and Fever: Case Report

Arrhythmias or conduction system disease are not the most common manifestation of COVID-19 infection in patients requiring hospital admission. Torsade de pointes typically occurs in bursts of self-limiting episodes with symptoms of dizziness and syncope. However, it may occasionally progress to ventricular fibrillation and sudden death. In this article, we report a case of COVID-19 patient who developed polymorphic ventricular tachycardia with torsade de pointes morphology with normal QTc interval in the setting of fever. An 81-year-old woman was admitted with symptoms of COVID-19. She was treated with hydroxychloroquine, azithromycin, and doxycycline at an outside facility and finished the treatment 5 days prior to admission to our facility. Her course was complicated by atrial fibrillation with rapid ventricular response requiring cardioversion. Later, she developed two episodes of polymorphic ventricular tachycardia with TdP morphology with normal QTc. There was a correlation with fever triggering the ventricular tachycardia. We advocated aggressive fever control given the QTc was normal and stable. Following fever control, the patient remained stable and had no abnormal rhythm. COVID-19 patients are prone to different arrhythmias including life-threatening ventricular arrhythmias with normal left ventricular systolic function and normal QTc, and they should be monitored for fever and electrolyte abnormality during their hospital stay.

[Incidence and Risk Factors of Hypokalemia in Tazobactam/Piperacillin-administered Patients]

Tazobactam/piperacillin (TAZ/PIPC) is a useful antimicrobial agent with broad antibacterial activity. Hypokalemia is considered a rare side effect of TAZ/PIPC; however, it may occur more often than previously thought. In this study, hypokalemia frequency and risk factors were examined in 420 patients treated with TAZ/PIPC. Our results demonstrated that the hypokalemia incidence was 24.8% (grade 1-2: 18.3%, grade 3-4: 6.4%). In addition, multivariate analysis revealed that age [odds ratio 1.057, 95% confidence interval 1.024-1.090, cutoff value 80.5 years] is a risk factor. Although the "Daily dosage/creatinine clearance" was not significant in multivariate analysis, univariate analysis indicated it be to be significant, with a cutoff value of 294.9 mg/mL/min. Furthermore, a "body mass index of 19.7 kg/m² or higher", "serum potassium level before administration of 3.95 mEq/L or more", and "no empirical treatment for administration purposes" appeared to prevent the hypokalemia development. Overall, the hypokalemia incidence rate in TAZ/PIPC-administered patients was as high as 20%, with patients aged >80.5 years considered a high-risk group. Thus, careful monitoring of potassium levels in patients treated with TAZ/PIPC, particularly those aged >81 years, is warranted.

Torsades de pointes and QT prolongation Associations with Antibiotics: A Pharmacovigilance Study of the FDA Adverse Event Reporting System

Introduction: Macrolides, linezolid, imipenem-cilastatin, fluoroquinolones, penicillin combinations, and ceftriaxone are known to be associated with Torsades de pointes/QT prolongation (TdP/QTP). Other antibiotics may also lead to TdP/QTP, but no study has systemically compared TdP/QTP associations for many available antibiotics. Objectives: The objective of this study was to evaluate the association between TdP/QTP and many available antibiotics using the FDA Adverse Event Report System (FAERS). Methods: FAERS reports from January 1, 2015 to December 31, 2017 were analyzed. The Medical Dictionary for Regulatory Activities (MedDRA) was used to identify TdP/QTP cases. We calculated the Reporting Odds Ratios (RORs) and corresponding 95% confidence intervals (95%CI) for the association between antibiotics and TdP/QTP. An association was considered to be statistically significant when the lower limit of the 95%CI was greater than 1.0. Results: A total of 2,042,801 reports (including 3,960 TdP/QTP reports) were considered, after inclusion criteria were applied. Macrolides had the greatest proportion of TdP/QTP reports. Of the 4,092 reports associated with macrolides, 108 reports (2.6%) were associated with TdP/QTP. Significant TdP/QTP RORs (95%CI) for the antibiotics were (in descending order): macrolides 14.32 (11.80-17.38), linezolid 12.41 (8.52-18.08), amikacin 11.80 (5.57-24.97), imipenem-cilastatin 6.61 (3.13-13.94), fluoroquinolones 5.68 (4.78-6.76), penicillin combinations 3.42 (2.35-4.96), and ceftriaxone 2.55 (1.41-4.62). Conclusion: This study confirms prior evidence for TdP/QTP associations with macrolides, linezolid, imipenem-cilastatin, fluoroquinolones, penicillin combinations, and ceftriaxone. This study also identifies a new association between amikacin and TdP/QTP.

Electrocardiographic manifestations in severe hypokalemia

Hypokalemia is one of the most common electrolyte disturbances in the clinic and it can increase the risk of life-threatening arrhythmias. Electrocardiographic characteristics associated with hypokalemia include dynamic changes in T-wave morphology, ST-segment depression, and U waves, which are often best seen in the mid-precordial leads (V2–V4). The PR interval can also be prolonged along with an increase in the amplitude of the P wave. We report a case of a patient with hypokalemia (1.31 mmol/L) who showed typical electrocardiographic characteristics of hypokalemia.

Drug-physiology interaction and its influence on the QT prolongation-mechanistic modeling study

The current study is an example of drug-disease interaction modeling where a drug induces a condition which can affect the pharmacodynamics of other concomitantly taken drugs. The electrophysiological effects of hypokaliemia and heart rate changes induced by the antiasthmatic drugs were simulated with the use of the cardiac safety simulator. Biophysically detailed model of the human cardiac physiology-ten Tusscher ventricular cardiomyocyte cell model-was employed to generate pseudo-ECG signals and QTc intervals for 44 patients from four clinical studies. Simulated and observed mean QTc values with standard deviation (SD) for each reported study point were compared and differences were analyzed with Student's t test (α = 0.05). The simulated results reflected the QTc interval changes measured in patients, as well as their clinically observed interindividual variability. The QTc interval changes were highly correlated with the change in plasma potassium both in clinical studies and in the simulations (Pearson's correlation coefficient > 0.55). The results suggest that the modeling and simulation approach could provide valuable quantitative insight into the cardiological effect of the potassium and heart rate changes caused by electrophysiologically inactive, non-cardiological drugs. This allows to simulate and predict the joint effect of several risk factors for QT prolongation, e.g., drug-dependent QT prolongation due to the ion channels inhibition and the current patient physiological conditions.