Geoffrey K Isbister1. 1. Charles Darwin University, Darwin and Department of Clinical Toxicology and Pharmacology, Calvary Mater Newcastle Hospital, Waratah, Australia. geoffrey.isbister@menzies.edu.au
Abstract
AIMS: To investigate serial electrocardiogram (ECG) parameters, haemodynamic changes and arrhythmias following venlafaxine overdose. METHODS: The study included 369 venlafaxine overdoses in 273 patients presenting to a toxicology unit where an ECG was available. Demographic information, details of ingestion, haemodynamic effects [heart rate and blood pressure (BP)] and complications (arrhythmias and conduction defects) were obtained. ECG parameters (QT, QRS) were measured manually and analysed by visual inspection, including plotting QT-HR pairs on a QT nomogram. RESULTS: The median ingested dose was 1500 mg [interquartile range (IQR) 600-3000 mg; range 75-13 500 mg). Tachycardia occurred in 54% and mild hypertension (systolic BP >140 mmHg) in 40%. Severe hypertension (systolic BP >180 mmHg) and hypotension (systolic BP <90 mmHg) occurred in 3% and 5%, respectively. No arrhythmias occurred based on continuous telemetry, and conduction defects were found in only seven of 369 admissions; five of these conduction defects were pre-existing abnormalities. In 22 admissions [6%, 95% confidence interval (CI) 4-10] there was an abnormal QT-HR pair, with larger doses being more likely to be associated with an abnormal QT. The median maximum QRS width was 85 ms (IQR 80-90 ms; range 70-145 ms) and the QRS was greater than 120 ms in only 24 admissions (7%, 95% CI 4-10). CONCLUSIONS: Venlafaxine overdose causes only minor abnormalities in the QT and QRS intervals, unlikely to be associated with major arrhythmias, except possibly with large doses.
AIMS: To investigate serial electrocardiogram (ECG) parameters, haemodynamic changes and arrhythmias following venlafaxineoverdose. METHODS: The study included 369 venlafaxineoverdoses in 273 patients presenting to a toxicology unit where an ECG was available. Demographic information, details of ingestion, haemodynamic effects [heart rate and blood pressure (BP)] and complications (arrhythmias and conduction defects) were obtained. ECG parameters (QT, QRS) were measured manually and analysed by visual inspection, including plotting QT-HR pairs on a QT nomogram. RESULTS: The median ingested dose was 1500 mg [interquartile range (IQR) 600-3000 mg; range 75-13 500 mg). Tachycardia occurred in 54% and mild hypertension (systolic BP >140 mmHg) in 40%. Severe hypertension (systolic BP >180 mmHg) and hypotension (systolic BP <90 mmHg) occurred in 3% and 5%, respectively. No arrhythmias occurred based on continuous telemetry, and conduction defects were found in only seven of 369 admissions; five of these conduction defects were pre-existing abnormalities. In 22 admissions [6%, 95% confidence interval (CI) 4-10] there was an abnormal QT-HR pair, with larger doses being more likely to be associated with an abnormal QT. The median maximum QRS width was 85 ms (IQR 80-90 ms; range 70-145 ms) and the QRS was greater than 120 ms in only 24 admissions (7%, 95% CI 4-10). CONCLUSIONS:Venlafaxineoverdose causes only minor abnormalities in the QT and QRS intervals, unlikely to be associated with major arrhythmias, except possibly with large doses.
Authors: A Biffi; F Rea; L Scotti; A Mugelli; E Lucenteforte; A Bettiol; A Chinellato; G Onder; C Vitale; N Agabiti; G Trifirò; G Roberto; G Corrao Journal: Eur J Clin Pharmacol Date: 2017-10-18 Impact factor: 2.953
Authors: Lauren M Behlke; Eric J Lenze; Vy Pham; J Philip Miller; Timothy W Smith; Yasmina Saade; Jordan F Karp; Charles F Reynolds; Daniel M Blumberger; Cristiana Stefan; Benoit H Mulsant Journal: J Clin Psychopharmacol Date: 2020 Nov/Dec Impact factor: 3.118
Authors: Rose Cairns; Emily A Karanges; Anselm Wong; Jared A Brown; Jeff Robinson; Sallie-Anne Pearson; Andrew H Dawson; Nicholas A Buckley Journal: BMJ Open Date: 2019-02-20 Impact factor: 2.692