Potassium channel blockers are medicines that you take for abnormal heart rhythms (arrhythmias). They’re called Class III antiarrhythmics and come in various forms and strengths. Each medicine has side effects and drug interactions. They treat heart rhythm problems that start in your heart’s upper or lower chambers.
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Potassium channel blockers are Class III antiarrhythmic drugs. They treat and prevent abnormal heart rhythms (arrhythmias). These rhythms may happen in your lower heart chambers (ventricles) or upper heart chambers (atria). Examples include atrial fibrillation, atrial flutter, SVTs and ventricular arrhythmias.
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By blocking potassium channels, these drugs give your heart a longer resting period between beats. This helps your heart beat in a normal rhythm.
Examples of this drug include:
A healthcare provider can give you these medicines by injection into a vein. You can also take them as a tablet, capsule or oral solution you swallow.
For injected versions of this drug, you’ll receive them from a healthcare provider. You may need to start taking certain potassium channel blockers while you’re in the hospital. This allows your healthcare team to monitor you and make sure the drug isn’t causing an abnormal heart rhythm.
When you go home from the hospital, follow your provider’s instructions for taking this medicine. For example, they might tell you to take it once a day. For another drug, it might be twice a day. Contact your provider if you miss a dose.
Side effects of potassium channel blockers include:
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Some of these medicines increase your risk of an abnormal heart rhythm called Torsades de Pointes. This can cause dizziness, fainting and cardiac arrest.
Grapefruit juice and St. John’s wort interact with some potassium channel blockers. These medicines can also interact with other drugs, including:
Before taking this medicine, tell your provider if you have:
Yes, potassium channel blockers may harm a fetus. Also, this medicine passes into breast milk. Healthcare providers don’t recommend breastfeeding while taking this drug.
An abnormal heart rhythm can interfere with your life. But potassium channel blockers may help get your heart back to a typical rhythm. Still, every medicine has side effects. Talk to your healthcare provider about the best treatment for your situation.
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Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
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