sábado, 7 de julio de 2012

Ondansetron y arritmias


Comunicación de seguridad de drogas de la FDA: Nueva información acerca de prolongacióan del intervalo QT con ondansetron
FDA Drug Safety Communication: New information regarding QT prolongation with ondansetron
Additional Information for Healthcare Professionals  (updated from 9/15/2011)
ECG changes including QT interval prolongation have been observed in patients receiving ondansetron. In addition, Torsade de Pointes, an abnormal, potentially fatal, heart rhythm, has been reported in some patients receiving ondansetron.
The use of a single 32 mg intravenous dose of ondansetron should be avoided.  New information indicates that QT prolongation occurs in a dose-dependent manner, and specifically at a single intravenous dose of 32 mg.
Patients who may be at particular risk for QT prolongation with ondansentron are those with congenital long QT syndrome, congestive heart failure, bradyarrhythmias, or patients taking concomitant medications that prolong the QT interval
Electrolyte abnormalities (e.g., hypokalemia or hypomagnesemia) should be corrected prior to the infusion of ondansetron.
The lower dose intravenous regimen of 0.15 mg/kg every 4 hours for three doses may be used in adults with chemotherapy-induced nausea and vomiting. However, no single intravenous dose of ondansetron should exceed 16 mg due to the risk of QT prolongation.
The new information does not change any of the recommended oral dosing regimens for ondansetron, including the single oral dose of 24 mg for chemotherapy induced nausea and vomiting.
The new information also does not change the recommended lower dose intravenous dosing to prevent post-operative nausea and vomiting.
Report adverse events involving ondansetron to the FDA MedWatch program using the information in the "Contact Us" box at the bottom of the page.
http://www.fda.gov/Drugs/DrugSafety/ucm310190.htm 


 
Efecto del ondansetron intravenoso sobre la prolongación del interval QT en pacientes con enfermedad cardiovascular y riesgo adicional de torsades de points; estudio prospectivo observacional. 
Effect of intravenous ondansetron on QT interval prolongation in patients with cardiovascular disease and additional risk factors for torsades: a prospective, observational study.
Hafermann MJ, Namdar R, Seibold GE, Page RL 2nd.
University of Washington Medical Center, Department of Pharmacy, Seattle, WA;
Drug Healthc Patient Saf. 2011;3:53-8. Epub 2011 Oct 3.
Abstract
BACKGROUND: The 5-hydroxytryptamine type 3 antagonists, or setrons (eg, ondansetron), are commonly used for nausea and vomiting in the hospital setting. In 2001, droperidol was given a black box warning because it was found to prolong the QT interval and induce arrhythmias. The setrons share with droperidol the same potential proarrhythmic mechanisms, but limited data exist concerning their effects on the QT interval in individuals at high risk for torsades de pointes. METHODS: Forty hospitalized patients admitted for heart failure or acute coronary syndromes with one or more risk factors for torsades de pointes and an order for intravenous ondansetron 4 mg were enrolled in this prospective, observational study. The QT interval corrected for heart rate (QTc) was obtained via a 12-lead electrocardiogram on admission and again 120 minutes after the first dose of ondansetron in order to determine the mean change in QTc following ondansetron exposure. RESULTS: The mean time interval between obtaining the baseline electrocardiogram and the second electrocardiogram following ondansetron administration was 3.5 ± 2.14 hours. In the total population, the QTc interval was prolonged by 19.3 ± 18 msec (P < 0.0001) 120 minutes after ondansetron administration. For patients with an acute coronary syndrome and those with heart failure, QTc was prolonged by 18.3 ± 20 msec (P < 0.0001) and 20.6 ± 20 msec (P < 0.0012), respectively. Following ondansetron exposure, 31% and 46% in the heart failure and acute coronary syndromes groups, respectively, met gender-related thresholds for a prolonged QTc. CONCLUSION: Our study found QTc prolongation due to ondansetron administration similar to that found in previous studies. When used in patients with cardiovascular disease (eg, heart failure or acute coronary syndromes) with one or more risk factors for torsades de pointes, ondansetron may significantly increase the QTc interval for up to 120 minutes after administration. From a patient safety perspective, patients who are at high risk for torsades de pointes and receiving ondansetron should be followed via telemetry when admitted to hospital.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3202761/?tool=pubmed
Atentamente
Anestesiología y Medicina del Dolor

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