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Journal of Obstrectic Anaesthesia and Critical Care
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 Table of Contents  
Year : 2012  |  Volume : 2  |  Issue : 2  |  Page : 103-104

Ondansetron-induced ventricular tachycardia in a patient of caesarian section

Department of Anesthesiology and Critical Care, S. N. Medical College, Agra, Uttar Pradesh, India

Date of Web Publication17-Dec-2012

Correspondence Address:
Arpita Saxena
Department of Anaesthesia and Critical care, S.N. Medical College, Agra, Uttar Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/2249-4472.104736

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We report a rare adverse effect of ondansetron in a 24-year-old female undergoing caesarian section, presenting as ventricular tachycardia and ectopics. Patient was treated with cardioversion and intravenous Amiodarone 150 mg.

Keywords: Ondansetron, synchronized electrical cardioversion, ventricular tachycardia

How to cite this article:
Saxena A, Chand T, Arya S K, Puri R, Mittal A, Shukla V. Ondansetron-induced ventricular tachycardia in a patient of caesarian section. J Obstet Anaesth Crit Care 2012;2:103-4

How to cite this URL:
Saxena A, Chand T, Arya S K, Puri R, Mittal A, Shukla V. Ondansetron-induced ventricular tachycardia in a patient of caesarian section. J Obstet Anaesth Crit Care [serial online] 2012 [cited 2023 Feb 1];2:103-4. Available from: https://www.joacc.com/text.asp?2012/2/2/103/104736

  Introduction Top

Ondansetron, 5-Hydroxytryptamine Type 3 (5-HT 3 ) antagonist has become the first-line drug for management of postoperative nausea and vomiting. Some common side-effects of ondansetron are fever, malaise, diarrhoea, constipation, and allergic reaction. Even though its clinical safety has been established in a large number of studies, its adverse effects have been reported and these include cardiovascular events like acute myocardial ischemia and arrhythmias [1] in adults.

  Case Report Top

A 24-year-old female with gravid 2, para 1 with previous one lower segment caesarian section with unremarkable past medical history presented to the hospital with full-term pregnancy. She was planned for elective caesarian section under spinal anaesthesia. Parturient followed standard fasting and pre-medication orders for elective caesarean (fasting six hours, ranitidine and metoclopramide). Preoperative blood investigations and vitals were essentially within normal limits. Subarachnoid block was given in lumbar 2-3 interspace with 26-Gauge spinal needle in left lateral position using 2.6 ml of Bupivacaine Hydrochloride (heavy). Level of sensory block was achieved up to sixth thoracic level. Intra-operatively her vitals were stable with blood pressure (BP) 106/70 and pulse rate 88/min. Just before rectus sheath closurestarted, ondansetron 4 mg was given intravenously over 2 min to prevent postoperative nausea and vomiting. Immediately within a minute of injecting ondansetron there was increase in pulse rate upto 130/min and blood pressure fell to 76/40 mmHg. Patient developed ventricular tachycardia with more than 10-12 ventricular ectopics per minute. At the same time patient was found delirious and irritable. Immediate synchronized electrical cardioversion (100 Joules) under midazolam cover 1 mg i/v was given to the patient. Patient responded well and pulse rate dropped to 110/min and blood pressure increased to 98/56 mmHg. Patient was also given amiodarone 150 mg intravenous slowly over 10 min. Ventricular ectopics disappeared and sinus rhythm was achieved. Surgery was uneventful with blood loss around 500 ml. Patient was shifted to intensive care unit and postoperative echocardiography was done, which was found normal. Postoperative serum electrolytes were within normal limits. There was no evidence of tachycardia, fall in blood pressure in the postoperative period.

  Discussion Top

The 5-HT 3 receptor antagonists are the primary drugs used to treat and prevent chemotherapy-induced nausea and vomiting. They are given intravenously about 30 min before commencement of a chemotherapy treatment. Ondansetron is also effective in controlling postoperative and post-radiation nausea and vomiting. Its safety and low cost of therapy suggests that it can be valuable in the treatment of gastroenteritis in children. [2] Large studies [3],[4],[5] have established its clinical safety, but some studies [6],[7] in adults have reported adverse effects like myocardial infarction and arrhythmias such as supra-ventricular tachycardia, ventricular tachycardia and atrial fibrillation. [8] There are only a few cases of dysrhythmia reported after administration of 4 mg ondansetron. [9]

Pharmacological action of ondansetron on the heart is potassium channel-mediated. Normally atrial, Purkinje fiber and ventricular cells action potential upstroke (Phase 1) is dependent on opening of Na+ channel. Action potential plateau phase (Phase 1, 2) reflects turning off of most of the Na+ current, waxing and waning of calcium current (mainly "L" type) and slow development of K+ current. Final repolarisation (Phase 3) results from complete inactivation of Na+ and Ca++ channel and increase in K+ permeability. Major potassium ion channels in this phase are rapidly acting and slowly acting,of this rapidly acting K+plays major role in Phase 3. [10]

The reasons for ventricular ectopics and tachycardia in the present case could be an adverse effect of ondansetron or inadvertent intravascular injection of bupivacaine during subarachnoid block. The former is the most likely cause as the ventricular ectopics and tachycardia occurred within one minute of its administration. Although rare, several mechanisms of ondansetron-induced arrhythmia have been discovered. Firstly, it blocks rapidly acting K+channel and prolongs repolarisation resulting in cardiac disturbances. [11] Secondly, cardiovascular effects of serotonin are mediated by 5HT 1 , 5HT 2 , 5HT 3 , 5HT 4 receptors. 5HT 3 receptors mediate Bezold-Jarisch reflex, which is an autonomic reflex consisting of bradycardia, hypotension and apnea. Suppression of this reflex by ondansetron leads to tachyarrhythmias. [1] Thirdly in some cases, 5HT 3 receptor blockade could possibly lead to unopposed action of 5HT 2 and 5HT 4 receptors, resulting in tachyarrhythmia and hypertension. [1]

This case reports a rare side-effect of ondansetron in a patient under spinal anaesthesia. Patient developed ventricular tachycardia after administration of ondansetron. This case nevertheless demonstrates the importance of vigilance for unexpected ventricular tachycardia in patients given ondansetron. Further studies are required to confirm ondansetron-induced ventricular arrhythmia and its clinical safety. Till such time, keeping patient safety in mind ondansetron should be used judiciously in patients.

  References Top

1.Kasinath NS, Malak O, Tetzlaff J. Atrial fibrillation after ondansetron for prevention and treatment of postoperative nausea and vomiting: A case report. Can J Anaesth 2003;50:229-31.  Back to cited text no. 1
2.Reeves JJ, Shannon MW, Fleisher GR. Ondansetron decreases vomiting associated with acute gastroenteritis: A randomized, controlled trial. Paediatrics 2002;109:e62.  Back to cited text no. 2
3.Einarson A, Maltepe C, Navioz Y, Kennedy D, Tan MP, Koren G. The safety of ondansetron for nausea and vomiting of pregnancy: A prospective comparative study. BJOG 2004;111:940-3.  Back to cited text no. 3
4.Tramèr MR, Reynolds DJ, Moore RA, McQuay HJ. Efficacy, dose-response, and safety of ondansetron in prevention of postoperative nausea and vomiting: A quantitative systematic review of randomized placebo-controlled trials. Anesthesiology 1997;87:1277-89.  Back to cited text no. 4
5.Larijani GE, Gratz I, Afshar M, Minassian S. Treatment of postoperative nausea and vomiting with ondansetron: A randomized, double-blind comparison with placebo. Anesth Analg 1991;73:246-9.  Back to cited text no. 5
6.Chandrakala R, Vijayashankara CN, Kumar KK, Sarala N. Ondansetron induced fatal ventricular tachycardia. Indian J Pharmacol 2008;40:186-7.  Back to cited text no. 6
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7.Afonso N, Dang A, Namshikar V, Kamat S, Rataboli PV. Intravenous ondansetron causing severe bradycardia: Two cases. Ann Card Anaesth 2009;12:170-1.  Back to cited text no. 7
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8.Ramsook C, Sahagun-Carreon I, Kozinetz CA, Moro-Sutherland D. A randomized clinical trial comparing oral ondansetron with placebo in children with vomiting from acute gastroenteritis. Ann Emerg Med 2002;39:397-403.  Back to cited text no. 8
9.Baguley WA, Hay WT, Mackie KP, Cheney FW, Cullen BF. Cardiac dysrhythmias associated with the intravenous administration of ondansetron and metaclopramide. Anesth Analg 1997;84:1380-1.  Back to cited text no. 9
10.Hume JR, Grant AO. Agents used in Cardiac Arrhythmias. In: Bertram G. Katzung, editor. Basic and Clinical Pharmacology. 10 th ed. Singapore: Tata Mc Graw-Hill; 2007. p. 213-5.  Back to cited text no. 10
11.Kuryshev YA, Brown AM, Wang L, Benedict CR, Rampe D. Interactions of the 5-hydroxytryptamine 3 antagonists class of antiemetic drugs with human cardiac ion channels. J Pharmacology Exp Ther 2000;295:614-20.  Back to cited text no. 11

This article has been cited by
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