[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/) › Ibutilide # Ibutilide ## Antiarrhythmics? Antiarrhythmics ## High alert? An error with this medicine can cause serious harm: double checks and protocols are used. An intravenous class III drug for rapid conversion of recent-onset atrial fibrillation or flutter. Torsades de pointes is its main danger. Updated Nov 1, 2026 ## Quick facts **Group** [Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/) **Target** Cardiac repolarising currents (slow inward sodium current and hERG/IKr) **Used for** Rapid conversion · Rapid conversion **Key effects** Headache · Nausea · Hypotension **Monitor** Continuous ECG during the infusion · Blood pressure **ATC** C01BD05 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Clinical What the labels mean - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action Ibutilide lengthens the action potential and refractoriness of atria and ventricles (class III effect). Its label describes delayed repolarisation mainly through activation of a slow inward, largely sodium, current; it also blocks IKr. It slightly slows the sinus rate and AV conduction and does not widen the QRS. - Ibutilide delays repolarisation in atria and ventricles - Refractoriness lengthens and the atrial re-entry stops - The QT prolongs: risk of torsades during and after the infusion ## Indications - Rapid conversion of recent-onset atrial fibrillation to sinus rhythm [Atrial fibrillation →](https://durgical.com/en/conditions/atrial-fibrillation/) - Rapid conversion of recent-onset atrial flutter to sinus rhythm [Atrial flutter →](https://durgical.com/en/conditions/atrial-flutter/) ## Adverse effects ### Common - Headache - Nausea - Hypotension - Bradycardia and bundle branch block ### Serious (rare, important) - Polymorphic ventricular tachycardia (torsades de pointes), sometimes needing cardioversion - Other new or worse ventricular arrhythmias ## Contraindications - Hypersensitivity to ibutilide or other components ## Key interactions **Class IA (disopyramide, quinidine, procainamide) and other class III drugs (amiodarone, sotalol)** Additive prolongation of refractoriness; not given together or shortly after the infusion **Phenothiazines, tricyclic and tetracyclic antidepressants, some H1 antihistamines** Higher risk of torsades through QT prolongation ## What is monitored - Continuous ECG during the infusion and for hours afterwards, until the QTc returns to baseline - Potassium and magnesium before treatment - Blood pressure ## Administration and safety - Given as a short intravenous infusion with continuous ECG monitoring; a defibrillator, pacing and drugs for polymorphic VT are at hand. - The infusion is stopped as soon as the arrhythmia ends, or if VT or marked QT prolongation appears. - Low potassium and magnesium are corrected before starting. ## Pregnancy and breastfeeding It was teratogenic and embryocidal in rats; it is used in pregnancy only if the benefit clearly justifies the risk. ## Nursing care - Stay with the patient and watch the monitor throughout the infusion. - Keep the ECG running after the infusion until the QTc is back to baseline, longer if arrhythmias appear. - Check that other antiarrhythmics are held as ordered. ## Pharmacokinetics **Distribution** Large volume of distribution; levels fall rapidly after the infusion **Metabolism** Liver, by oxidation of its side chain; kinetics vary widely between people **Onset and duration** Conversion, when it happens, usually occurs during or soon after the infusion ## Memory aid IBUTILIDE: In By drip, Undo flutter, Torsades In Line: watch the monitor until the QT is back. ## Test yourself Think of the answer, then tap the question to see it. ## For which arrhythmias is intravenous ibutilide used? Rapid conversion of recent-onset atrial fibrillation or atrial flutter to sinus rhythm. ## How long is the ECG monitored after an ibutilide infusion? Continuously for several hours, until the QTc returns to baseline, and longer if arrhythmias appear. ## What is corrected before giving ibutilide, and why? Low potassium and magnesium, to reduce the risk of torsades de pointes. [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/ibutilide/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## What the labels mean **High alert** An error with this medicine can cause serious harm: double checks and protocols are used. ## Connections ## Related drugs 4 - [Dofetilide](https://durgical.com/en/pharmacology/dofetilide/) - [Amiodarone](https://durgical.com/en/pharmacology/amiodarone/) - [Sotalol](https://durgical.com/en/pharmacology/sotalol/) - [Magnesium sulfate](https://durgical.com/en/pharmacology/magnesium-sulfate/) ## Related conditions 2 - [Atrial fibrillation](https://durgical.com/en/conditions/atrial-fibrillation/) - [Atrial flutter](https://durgical.com/en/conditions/atrial-flutter/) [← Back to the class: Antiarrhythmics](https://durgical.com/en/pharmacology/classes/antiarrhythmics/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [DailyMed - IBUTILIDE FUMARATE injection, solution](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=0cf8724a-f0d1-4ce2-b7c1-cf5fac345fd0) (DailyMed (U.S. National Library of Medicine), 2025); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=C01BD05) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/ibutilide/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/ibutilide/