Which descriptions are characteristics of Class III Antidysrhythmic drugs?

Class III antidysrhythmic drugs work by inhibiting delayed rectifier potassium currents. The characteristic action of this class is the prolongation of repolarization. They prolong action potential duration, increase effective refractory period (resting state in a depolarized cardiac cell), and widen QT interval.

Is amiodarone a class 3 antiarrhythmic?

Amiodarone is a class III antiarrhythmic, based on the benzofuran structure used in atrial and ventricular fibrillation therapy 12. Amiodarone is a multichannel blocker affecting delayed rectifier IKr, sodium channel and L‐type calcium currents.

Is metoprolol a Class II?

Class II agents These agents are particularly useful in the treatment of supraventricular tachycardias. They decrease conduction through the AV node. Class II agents include atenolol, esmolol, propranolol, and metoprolol.

What is the classification of amiodarone?

Amiodarone belongs to the group of medicines known as antiarrhythmics. It works directly on the heart tissue and will slow the nerve impulses in the heart. This helps keep your heart rhythm normal. This medicine is available only with your doctor’s prescription.

When is amiodarone contraindicated?

Amiodarone therapy is contraindicated in patients with second- or third-degree heart block who do not have a pacemaker. Intravenously administered amiodarone causes heart block or bradycardia in 4.9 percent of patients and hypotension in 16 percent.

What do Class III antiarrhythmic drugs do?

Class III antiarrhythmic drugs act by blocking repolarising currents and thereby prolong the effective refractory period of the myocardium. This is believed to facilitate termination of re-entry tachyarrhythmias. This class of drugs is developed for treatment of both supraventricular and ventricular arrhythmias.

Which of the following drugs is a Class III antiarrhythmic agent that is effective in the acute management of atrial fibrillation or atrial flutter of recent onset?

Currently, the class III antiarrhythmic agents sotalol and dofetilide are FDA approved for use in treating atrial arrhythmias; however, amiodarone is also used widely for maintenance of sinus rhythm in patients with AF.

Which antiarrhythmic drug has both Class 2 and 3 activity?

Amiodarone also exerts sympatholytic, sodium, and calcium antagonistic properties that decrease conduction through the AV and sinus node. Sotalol shares class II and class III antiarrhythmic properties.

What are drug names of Class III antidysrhythmics?


  • Dilantin 125
  • Lidocaine
  • Lidocaine CV
  • Lidopen
  • Mexiletine
  • Phenytek
  • Phenytoin
  • What are Class III drugs?

    Class III – low permeability, high solubility . Example: cimetidine; The absorption is limited by the permeation rate but the drug is solvated very fast. If the formulation does not change the permeability or gastro-intestinal duration time, then class I criteria can be applied. Class IV – low permeability, low solubility . Example: Bifonazole

    What are Class II medications?

    Class II – high permeability, low solubility. Example: glibenclamide, bicalutamide, ezetimibe, aceclofenac. The bioavailability of those products is limited by their solvation rate. A correlation between the in vivo bioavailability and the in vitro solvation can be found. Class III – low permeability, high solubility.

    What are the different types of antiarrhythmic drugs?

    Class I agents interfere with the sodium (Na+) channel.

  • Class II agents are anti- sympathetic nervous system agents. Most agents in this class are beta blockers.
  • Class III agents affect potassium (K+) efflux.
  • Class IV agents affect calcium channels and the AV node.
  • Class V agents work by other or unknown mechanisms.