Mexiletine

Mexiletine

Mexiletine treats life-threatening heart rhythm problems and works as a powerful medication for patients with dangerous ventricular arrhythmias. This Class 1B antiarrhythmic drug blocks sodium channels in the heart and helps maintain normal electrical activity during irregular patterns.

The medication does more than control heart rhythm—it helps manage chronic pain and muscle stiffness conditions called myotonia. Doctors prescribe this treatment for patients with serious arrhythmias that need intervention. This article covers everything about this crucial medication—from its effects in your body to dosage information and what side effects mean.

What is Mexiletine?

Mexiletine belongs to a Class IB antiarrhythmic medicine and comes as an oral capsule. Its fast onset and offset kinetics make it stand out from other heart medications. Mexiletine slows nerve impulses in the heart. The medication makes heart tissue less responsive to abnormal electrical signals that could trigger dangerous rhythm problems. These properties make it work better at faster heart rates with minimal effects at slower rates. 

Mexiletine Uses

Doctors mainly prescribe mexiletine to treat confirmed ventricular arrhythmias that need intervention. Other indications are

• Chronic pain conditions, including diabetic neuropathy and peripheral nerve injuries
• Muscle stiffness from myotonic dystrophy (Steinert's disease)
• Nondystrophic myotonias like Thomsen syndrome or Becker syndrome

How and When to Use Mexiletine Tablet

• Patients should take mexiletine exactly as their doctor prescribes, even if they feel better. 
• The medication works best with food, right after meals, or with milk. 
• Take an antacid to avoid stomach upset. 
• Blood levels need to stay consistent, so taking doses at equal intervals throughout the day helps the medicine work better. 
• Most people take it three times daily, about every eight hours.

Side Effects of Mexiletine Tablets

Common side effects include:

• Digestive issues: heartburn, nausea, vomiting
• Nervous system effects: dizziness, lightheadedness, trembling hands
• Coordination difficulties and unsteadiness while walking

Serious side effects:

• Chest pain
• Fast or irregular heartbeat
• Breathing problems. 
• Seizures (rare)
• Unusual bleeding or bruising

Precautions

• Your doctor needs to check regularly to see how mexiletine affects your body and adjust your dose if needed. 
• Inform your dental or surgical staff about your mexiletine use before any surgery or emergency treatment. 
• The medication might make you dizzy or less alert, so avoid driving or using machinery until you know how it affects you. 
• Patients with first-degree heart block need careful evaluation because mexiletine could make their heart condition worse.
• You should never change your dosage without your doctor's guidance.

How Mexiletine Tablet Works

The medication blocks voltage-gated sodium channels in the heart. This action slows down action potential rises during Phase 0 of cardiac electrical activity. The drug shortens the action potential duration and reduces refractoriness in heart tissues. Mexiletine doesn't significantly change resting membrane potential, sinus node function, or QT intervals.

Can I Take Mexiletine with Other Medicines?

Many medications interact with mexiletine, so you need to tell your doctor about everything you take. Your body processes mexiletine through CYP2D6 and CYP1A2 enzymes, which means other drugs affecting these pathways can change its levels in your body.

These medications might lower mexiletine levels:

• Alosetron
• Carbamazepine
• Cimetidine 
• Dofetilide
• Fluvoxamine
• Fluoxetine
• Melatonin
• Pefloxacin
• Phenobarbital
• Phenytoin 
• Propafenone
• Quinidine
• Rifampin 
• Smoking or tobacco use
• Theophylline
• Tizanidine

Mexiletine can reduce caffeine clearance and increase its effect, which might concern patients with heart rhythm problems.

Dosing information

Standard treatment usually needs 150-200 mg of mexiletine two to three times daily. New patients usually start with 200 mg every eight hours if rapid control isn't needed. Your doctor might adjust this dose every 2-3 days until finding the right balance.

Your doctor may prescribe these doses if quick control of ventricular arrhythmias is needed:

• An original loading dose of 400 mg
• Followed by 200 mg eight hours later

Patients with severe liver problems need lower doses and closer monitoring. 

Conclusion

Mexiletine is a great medication that helps patients with serious heart rhythm problems. Doctors used it mainly for ventricular arrhythmias, but this versatile drug also helps people manage chronic pain and muscle stiffness.

When it comes to strong heart medications, putting safety first is crucial. It is essential to have regular doctor visits while you are on mexiletine. Make sure to call your doctor if you notice any side effects.

Mexiletine isn't right for everyone, particularly if you have certain heart conditions or take medications that interact with it. But for patients who need it, this drug controls dangerous heartbeats and eases specific pain problems. Under proper medical supervision, mexiletine helps many patients lead healthier, more comfortable lives. 

FAQs

1. Is Mexiletine high risk?

Yes, mexiletine carries certain risks. The medication comes with a black box warning based on the Cardiac Arrhythmia Suppression Trial's findings. The drug can also cause serious side effects that impact multiple body systems.

2. Is Mexiletine an antibiotic?

No, mexiletine isn't an antibiotic. This medication belongs to a class of drugs called antiarrhythmics. It functions as a class IB antiarrhythmic drug that shares structural similarities with lidocaine.

3. How long does Mexiletine take to work?

The therapeutic effects usually begin 30 minutes to two hours after taking the medicine.

4. What happens if I miss a dose?

You should take the missed dose once you remember it. However, if it's nearly time for your next scheduled dose, continue with your regular schedule. Never take a double dose to make up for a missed one.

5. What happens if I overdose?

Overdose symptoms include:

• Drowsiness and confusion
• Nausea and vomiting
• Seizures and paraesthesia
• Heart block, bradycardia, or asystole
• Cardiovascular collapse and coma

You should contact emergency services immediately if you suspect an overdose.

6. Who cannot take Mexiletine?

Patients with cardiogenic shock or second/third-degree heart block (without a pacemaker) should not use mexiletine.

7. When should I take Mexiletine?

Taking mexiletine with food, milk, or an antacid helps prevent stomach upset. Take your medicine as scheduled by your doctor to maintain a steady concentration in your blood for optimal effect.

8. How many days to take Mexiletine?

You should continue taking mexiletine exactly as prescribed, even if you feel better. Your specific condition & response to treatment will determine the duration.

9. When to stop Mexiletine?

You should stop taking mexiletine and get medical help right away if you have chest pain, irregular heartbeat or breathing problems. Your doctor may need to stop this medicine if you develop side effects you cannot tolerate, especially stomach problems.

10. Is it safe to take Mexiletine daily?

Many patients do well with daily use under a doctor's watchful eye. Studies show that mexiletine has an impact on making life better for people with nondystrophic myotonia. It helps to ease stiffness and boost the quality of life. Most patients handle it without problems.

11. What is the best time to take Mexiletine?

You should take it right after meals or with milk/antacids to help prevent stomach upset.

12. What to avoid when taking Mexiletine?

Wait to drive until you know how Mexiletine affects you. Stay away from drinks with caffeine since mexiletine cuts caffeine clearance by half.

13. What happens when you stop taking Mexiletine?

Your condition could get worse if you suddenly stop taking mexiletine. Always talk to your doctor first.

14. Does Mexiletine make you gain weight?

Weight gain rarely shows up as a side effect of mexiletine.

15. Does Mexiletine affect the kidneys?

The kidneys need careful monitoring with mexiletine use. Doctors must adjust doses carefully for patients with serious kidney problems. Regular kidney function tests help track any changes.