What is Mexiletine: Uses, Dosage, Side Effects and More

Mexiletine is a prescription medication that helps control irregular heartbeats by stabilizing your heart's electrical activity. This oral medication belongs to a class of drugs called antiarrhythmics, which work like gentle electrical regulators to keep your heart beating in a steady, healthy rhythm.

You might feel overwhelmed hearing about heart rhythm medications, but mexiletine has been safely used for decades to help people live more comfortable lives. Think of it as a supportive friend for your heart, helping it maintain its natural pace when things get a bit chaotic.

What is Mexiletine?

Mexiletine is a sodium channel blocker that specifically targets the electrical pathways in your heart muscle. It's what doctors call a Class IB antiarrhythmic medication, which means it works by slowing down certain electrical signals that can cause your heart to beat irregularly.

This medication comes in capsule form and is typically taken by mouth two to three times daily. Your doctor will prescribe mexiletine when other treatments haven't been effective or when your specific type of heart rhythm problem responds best to this particular medication.

The drug has been around since the 1970s and has a well-established safety profile when used under proper medical supervision. It's considered a moderately strong heart medication that requires careful monitoring but can be very effective for the right patients.

What is Mexiletine Used For?

Mexiletine is primarily prescribed to treat ventricular arrhythmias, which are irregular heartbeats that start in the lower chambers of your heart. These types of rhythm problems can feel like your heart is skipping beats, racing, or beating too hard.

Your doctor might recommend mexiletine if you experience frequent premature ventricular contractions (PVCs) that cause bothersome symptoms. PVCs are extra heartbeats that can make you feel like your heart is fluttering or pounding, especially when you're trying to rest or sleep.

The medication is also used to prevent more serious ventricular arrhythmias, including ventricular tachycardia, which is when your heart beats dangerously fast. In some cases, doctors prescribe it for patients who have survived certain types of heart attacks and need ongoing protection against rhythm problems.

Less commonly, mexiletine may be used off-label for certain nerve pain conditions or muscle disorders, though this requires very specialized medical oversight. Your doctor will only consider these uses if standard treatments haven't provided adequate relief.

How Does Mexiletine Work?

Mexiletine works by blocking sodium channels in your heart muscle cells, which helps slow down the electrical signals that can cause irregular heartbeats. Think of it as installing speed bumps on the electrical highways of your heart to prevent signals from racing too quickly.

When your heart cells receive electrical signals, they normally open channels that allow sodium to flow in, triggering a heartbeat. Mexiletine partially blocks these channels, making it harder for abnormal electrical signals to trigger irregular beats while still allowing normal heart rhythm to continue.

This medication is considered moderately strong among heart rhythm drugs. It's not as aggressive as some Class I antiarrhythmics, but it's more potent than simple beta-blockers, which makes it effective for stubborn rhythm problems that don't respond to gentler treatments.

The drug typically starts working within a few hours of taking it, but you might not feel the full benefits for several days or even weeks. Your heart needs time to adjust to the medication's effects, and your doctor will monitor your response carefully during this period.

How Should I Take Mexiletine?

Take mexiletine exactly as your doctor prescribes, usually two to three times daily with food or milk. Taking it with food helps reduce stomach upset and can actually improve how well your body absorbs the medication.

Swallow the capsules whole with a full glass of water, and try to take your doses at the same times each day. This helps maintain steady levels of the medication in your bloodstream, which is important for consistent heart rhythm control.

You can take mexiletine with most foods, but avoid large amounts of acidic foods or drinks around dose times, as these might affect how your body processes the medication. Regular meals work perfectly fine, and there's no need to follow a special diet unless your doctor recommends one.

If you have trouble remembering doses, consider setting phone alarms or using a pill organizer. Consistent timing helps the medication work most effectively, so developing a routine that works with your daily schedule is really important.

Never crush or open the capsules, as this can affect how the medication is released in your body. If you have difficulty swallowing capsules, talk to your doctor about alternative formulations or techniques that might help.

How Long Should I Take Mexiletine For?

The length of mexiletine treatment varies greatly depending on your specific condition and how well you respond to the medication. Some people need it for just a few months, while others may take it for years or even long-term to maintain heart rhythm stability.

Your doctor will typically start with a trial period of several weeks to see how your heart responds and whether you experience any bothersome side effects. During this time, you'll likely have regular check-ups and possibly heart rhythm monitoring to track your progress.

For people with chronic heart rhythm problems, mexiletine might become a long-term medication, similar to how some people take blood pressure medications for life. The goal is to find the right balance between controlling your symptoms and minimizing any side effects.

Never stop taking mexiletine suddenly without talking to your doctor first. Stopping abruptly can sometimes cause your heart rhythm problems to return more severely than before, a phenomenon called rebound arrhythmias.

Your doctor will periodically review whether you still need the medication and might adjust your dose or suggest trying a break from treatment if your heart rhythm has been stable for an extended period.

What Are the Side Effects of Mexiletine?

Like most heart medications, mexiletine can cause side effects, though many people tolerate it well once their body adjusts to the medication. The most common side effects are usually mild and often improve after the first few weeks of treatment.

Here are the side effects you might experience, starting with the most common ones that typically aren't serious:

• Nausea or stomach upset, especially when first starting the medication
• Dizziness or lightheadedness, particularly when standing up quickly
• Tremor or slight shaking of your hands
• Fatigue or feeling more tired than usual
• Heartburn or indigestion
• Coordination problems or feeling slightly unsteady
• Sleep disturbances or vivid dreams

These common side effects often fade as your body gets used to the medication, but let your doctor know if they persist or bother you significantly.

Some people experience more concerning side effects that require medical attention. While these are less common, it's important to recognize them:

• New or worsening heart rhythm problems
• Severe dizziness or fainting spells
• Chest pain or breathing difficulties
• Persistent nausea or vomiting
• Severe tremors or coordination problems
• Mood changes or confusion

Rarely, mexiletine can cause more serious side effects that need immediate medical care. These include severe allergic reactions, liver problems, or blood disorders, though these occur in less than 1% of people taking the medication.

Contact your doctor right away if you develop a rash, yellowing of your skin or eyes, unusual bruising, or persistent fever while taking mexiletine. These symptoms are uncommon but could indicate a serious reaction that needs prompt attention.

Who Should Not Take Mexiletine?

Mexiletine isn't suitable for everyone, and your doctor will carefully review your medical history before prescribing it. Certain heart conditions make mexiletine unsafe or potentially dangerous to use.

You should not take mexiletine if you have certain types of heart block or severe heart failure, as the medication could worsen these conditions. Your doctor will perform an electrocardiogram (ECG) to check your heart's electrical activity before starting treatment.

People with liver problems may not be able to take mexiletine safely, since the liver processes this medication. If you have a history of liver disease or take other medications that affect liver function, your doctor will need to monitor you very closely.

Pregnant women should generally avoid mexiletine unless the benefits clearly outweigh the risks, as its effects on developing babies aren't fully understood. If you're breastfeeding, mexiletine can pass into breast milk and may affect your baby.

Tell your doctor about all medications you're taking, including over-the-counter drugs and supplements. Mexiletine can interact with many other medications, particularly other heart rhythm drugs, certain antibiotics, and some antidepressants.

If you have kidney problems, seizure disorders, or a history of psychiatric conditions, your doctor will need to weigh the benefits and risks carefully before prescribing mexiletine.

Mexiletine Brand Names

Mexiletine is available under several brand names, with Mexitil being the most commonly recognized. However, most pharmacies now carry generic versions of mexiletine, which are just as effective as the brand-name versions.

Generic mexiletine has been available for many years and meets the same quality standards as brand-name medications. Your insurance may prefer the generic version, and it's typically much more affordable without any difference in effectiveness.

Some other brand names you might see include Mexitil and various generic formulations from different manufacturers. The important thing is the active ingredient, mexiletine hydrochloride, which is the same regardless of the brand.

If you're switching between different manufacturers of generic mexiletine, let your doctor know, as there can be slight differences in how different formulations are absorbed by your body.

Mexiletine Alternatives

If mexiletine isn't right for you or doesn't control your heart rhythm effectively, several other medications can treat similar conditions. Your doctor might consider other antiarrhythmic drugs like flecainide, propafenone, or amiodarone.

Flecainide is another Class I antiarrhythmic that works similarly to mexiletine but may be better tolerated by some people. It's often used for similar types of heart rhythm problems and might be an option if mexiletine causes too many side effects.

Beta-blockers like metoprolol or atenolol are gentler alternatives that might work for less severe rhythm problems. These medications slow your heart rate and can be effective for certain types of irregular heartbeats without the stronger side effects of mexiletine.

For more serious rhythm problems, your doctor might consider amiodarone, which is a very potent antiarrhythmic medication. However, amiodarone has its own set of side effects and requires careful monitoring.

Non-medication treatments like catheter ablation or implantable devices might be alternatives for some people, especially if medications aren't controlling their symptoms effectively.

Is Mexiletine Better Than Flecainide?

Whether mexiletine is better than flecainide depends entirely on your specific heart condition and how your body responds to each medication. Both drugs work on heart rhythm problems, but they have different strengths and side effect profiles.

Mexiletine is often chosen for people who have had heart attacks or have certain structural heart problems, as it's generally safer in these situations than flecainide. It's also preferred when people have had bad reactions to other antiarrhythmic medications.

Flecainide might be preferred for people with structurally normal hearts who have atrial fibrillation or certain types of supraventricular tachycardia. It's often better tolerated and may require less frequent dosing than mexiletine.

Your doctor will consider factors like your specific type of arrhythmia, your overall heart health, other medical conditions you have, and your previous responses to heart medications when choosing between these options.

Sometimes doctors try one medication first and then switch to the other if the first choice doesn't work well or causes bothersome side effects. This trial-and-error approach is common and normal in heart rhythm management.