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Medications Commonly Used to Treat Arrhythmias

Pharmacist discussing medication with patient

While a resting heart rate — the number of times your heart beats per minute when you’re at rest — will vary from one individual to the next, the healthy range for an adult is between 60 and 100 beats per minute. However, when there are issues with your heart’s electrical signals, which trigger each individual heartbeat, your heart may beat too quickly, too slowly, or irregularly. This is called an arrhythmia.

The best course of action depends on the type of arrhythmia you have and your overall health. Many cases of mild arrhythmias do not require any treatment. But your doctor may recommend medication to control or resolve your arrhythmia if there is a risk that your arrhythmia could cause more serious heart health issues.

Below, we explain more about the primary types of arrhythmias and the medications most commonly used to treat them.

Types of arrhythmias

Arrhythmias are categorized by the speed of the resulting heart rate and the area of the heart in which they originate.


A tachycardia is a fast heart rate, typically over 100 beats per minute when you’re at rest. There are many different types of tachycardias, including the following:

  • Atrial fibrillation is a rapid heart rate caused by irregularities in the electrical signals in the heart’s upper chambers, or atria. The condition may be temporary in some cases, but it often requires retreatment. It has been linked to more serious health issues including strokes.
  • Ventricular tachycardia is a rapid but steady heart rate caused by irregular electric signals in the heart’s lower chambers, or ventricles. The condition may lead to health complications depending on your overall cardiovascular health.


A bradycardia is a slow heart rate, typically under 60 beats per minute when you’re at rest. There are several types of bradycardias, including:

  • Sick sinus syndrome is a condition in which your sinus node — the heart’s natural pacemaker — doesn’t properly send electrical signals, causing your heart rate to beat slowly. (In some individuals, sinus node problems may result in a heart rate that alternates between too slow and too fast, which is also called bradycardia-tachycardia syndrome.)
  • Heart block, or atrioventricular block, is a condition in which electrical signals running through the atria don’t reach the ventricles. There’s a wide range in the severity of heart blocks, so they are subclassified into first-degree (mildest), second-degree, and third-degree (complete) heart blocks.

Premature heartbeats

It’s also possible to experience a premature heartbeat, which often feels like a skipped heartbeat but is actually an additional beat. Premature heartbeats may occur when you are at rest, or they may be caused by stress, physical exertion, or stimulants like caffeine or nicotine.

For many individuals, premature heartbeats do not lead to more serious health problems, but it may trigger a more persistent arrhythmia in others. If you have a preexisting heart disease, you are more likely to experience complications as the result of a premature heartbeat.

Monitoring your heart rate and diagnosing an arrhythmia

Regularly monitoring your heart rate and heart rhythm can help you identify any potential issues in advance and avoid more serious health complications. Read our previous blog, ‘What Your Heart Rate Can Tell You About Your Health’ for additional guidance on measuring your resting heart rate. And if you have any concerns about your heart rate, consult with your doctor for an evaluation of any heart-related health issues.

To make a formal diagnosis of an arrhythmia, your doctor may use one or more tests to capture your heart’s rhythm. The process often begins with an electrocardiogram (ECG), a test performed in your doctor’s office in which patches attached to various places on your chest, arms, and legs record your heart’s activity.

If you have a chronic, consistent arrhythmia, the ECG may accurately capture your arrhythmia. However, if your arrhythmia is less frequent, an ECG may not necessarily give your doctor the information needed for a diagnosis. If that’s the case, they may recommend additional tests, including monitors you can use at home to record your heart’s activity over a longer period of time.

Treating an arrhythmia with antiarrhythmics

Antiarrhythmics help restore a regular heart rhythm by acting on the electrical currents that cause your heart to beat. They are most commonly used to treat tachycardias or premature heartbeats, and the majority are taken orally as a pill on an ongoing basis.

These are some of the most commonly prescribed antiarrhythmics and their side effects:


Amiodarone works by slowing down your heart’s nerve activity. It will likely take several weeks of amiodarone use before you experience the medication’s full effects.

It isn’t uncommon to experience nausea, vomiting, constipation, loss of appetite, abdominal pain, or a combination of these effects from taking amiodarone. For that reason, your doctor may recommend that you take amiodarone with meals.

Additional side effects include tremors, lack of coordination, weakness, fatigue, and difficulty sleeping. If any of these are severe or long-lasting, or if you experience more serious side effects such as abdominal swelling or painful breathing, contact your doctor right away.


Flecainide is typically started in the hospital if you are admitted for an arrhythmic-related health issue so that your doctor can closely monitor your response to it. It comes in tablet form and is usually taken twice a day. If you experience an upset stomach from the medication, your doctor may recommend that you take it with food or milk.

Flecainide is most effective when there is a constant level of it in your bloodstream so it’s important that you take it exactly as directed by your doctor. Abruptly stopping use of flecainide can cause serious health complications, so be sure to follow your doctor’s recommendations and consult with them if you have any concerns.

Common side effects of flecainide include nausea, vomiting, or diarrhea; loss of appetite; tremors; blurred vision; sleep disruptions; weakness; and dizziness or faintness. Contact your doctor if these side effects are severe or long-lasting. If you experience any severe side effects such as chest pain, yellow eyes or skin, fever, or difficulty breathing, contact your doctor as soon as possible.

Standing up slowly from sitting or lying down can alleviate dizziness and drowsiness caused by the medication. You should also ask your doctor if there are any activities to avoid while taking this medication given these side effects.


Propafenone acts on the heart muscle to improve your heart rhythm. It is typically taken three times a day. You may begin taking it in the hospital so that your doctor can observe how it affects you.

To maintain a consistent level of propafenone in your bloodstream, it’s important to follow your healthcare provider’s recommendations and to take the medication exactly as prescribed. If you have any concerns about taking this medication, consult with your doctor, as abruptly stopping use of propafenone may lead to an irregular heartbeat. One exception is if you experience excessive drowsiness or a slow or irregular heartbeat, in which case you should stop taking the medication right away and contact your doctor.

Side effects are less common with propafenone than with other antiarrhythmics. However, you may experience nausea, vomiting, constipation, diarrhea, loss of appetite, stomach cramps, weakness or muscle aches. Contact your doctor if you have any concerns about these side effects.

Ask your doctor about any possible food restrictions or necessary changes to your diet, as potassium can interact with propafenone.

Dronedarone (Multaq®)

Dronedarone is primarily recommended for individuals who have previously had atrial fibrillation but now have a normal heart rhythm. It can reduce the likelihood of being hospitalized for the condition in the future.

Your doctor will likely consider your overall health when determining if dronedarone is a good fit for you, as the medication may increase your risk for complications of other heart conditions. It is not typically recommended for individuals who have severe heart failure or worsening heart failure symptoms, or if your atrial fibrillation has remained consistent.

This medication has been known to interact with other medications, including other heart rhythm medications; antiviral medications like ritonavir; certain antibiotics including clarithromycin and telithromycin; certain antidepressants including amitriptyline, clomipramine, and nefazodone; antifungal medications like itraconazole, ketoconazole, and voriconazole; and antipsychotic medications like chlorpromazine, fluphenazine, and thioridazine. Make sure your doctor is aware of any medications you take.

Intravenous antiarrhythmics

Antiarrhythmics may also be administered intravenously in the hospital during a medical emergency. Ibutilide (Corvert®) and lidocaine (Xylocaine®) are two of the most commonly used antiarrhythmics that are administered through an IV.

General guidance about antiarrhythmic use

There are some general practices to follow when taking any medication in this class to avoid more serious health complications and manage side effects:

  • Inform your doctor of any underlying health conditions you have, as these may interact with your medication, especially kidney disease, congestive heart failure, liver disease, diabetes, or respiratory disease.
  • Your doctor may recommend exams, electrocardiograms (ECGs), and blood tests to monitor the medication’s effectiveness. Stay current with these follow-up appointments and lab work. 
  • Use caution when driving, particularly while you are still adjusting to the medication, and ask your doctor if there are any activities that you should avoid.

Depending on the type of arrhythmia you have and your overall health history, your doctor may also recommend calcium channel blockers or beta blockers. Here’s what to know about these medication classes.

Calcium channel blockers

If you have chest pain or high or low blood pressure in addition to your arrhythmia, your doctor may prescribe a calcium channel blocker. Commonly used to treat high blood pressure, calcium channel blockers open up narrowed blood vessels, allowing for more blood to flow to your heart. They are also used to treat arrhythmias since the opening of blood vessels can also slow your heart rate.

Most calcium channel blockers prescribed for arrhythmias are taken orally as pills, but some of them may be taken intravenously, which is when a medication is sent directly into your veins using a needle or a tube, typically in a hospital or doctor’s office.

Calcium channel blockers commonly used to treat arrhythmias include:

  • Amlodipine (Norvasc®)
  • Diltiazem (Cardizem®, Tiazac®)
  • Nifedipine (Procardia®)
  • Verapamil (Calan®, Verelan®)

Common calcium channel blocker side effects include dizziness, constipation, and headaches. More severe side effects include rash or swelling in your legs and feet. Contact your doctor if you have any concerns about these side effects.

Beta blockers

Beta blockers are commonly used to treat high blood pressure. Since they cause the heart to beat more slowly and less forcefully, they are also effective at treating tachycardias.

Beta blockers commonly used to treat tachycardias include:

  • Atenolol (Tenormin®)
  • Bisoprolol (Zebeta®)
  • Metoprolol tartrate (Lopressor®)
  • Metoprolol succinate (Toprol-XL®)
  • Acebutolol (Sectral®)
  • Propranolol (Inderal®)

Common beta blocker side effects include cold hands, fatigue, headache, and weight gain. They may also affect your digestive system.

If you have diabetes and take insulin, it’s important to check your blood sugar levels often while taking beta blockers as beta blockers may block typical signs of low blood sugar such as a rapid heart rate. Beta blockers are not typically used by people with asthma, as they may trigger severe asthma attacks.

If your arrhythmia puts you at a greater risk for blood clots or a stroke caused by a blood clot, your doctor may add an anticoagulant to your medication protocol. These medications reduce the blood’s ability to form new blood clots and prevent existing clots from growing. They will not address your arrhythmia, however, so they are typically taken in combination with one of the medications described above.

Choose a pharmacy that never skips a beat

At Alto, we’re committed to making it as simple as possible to manage your arrhythmia and strengthen your heart. We offer free same-day delivery and medication management tools like reminders and auto refills in our app. And our team of pharmacists is always here to answer your questions by phone or through the Alto app, and will even remind you when your medications are due for a refill.

Reach out any time via phone at 1-800-874-5881 or in-app messaging.

