What Is a Sodium Channel Blocker?

A sodium channel blocker is a medication that is categorized as a Class I antiarrhythmic drug. This means that it works to correct abnormal heart rhythms by affecting the electrical impulses. These drugs may be prescribed to patients who have suffered a heart attack, remain hospitalized, and still suffer from abnormal heart rhythms. Some examples of these medications include flecainide, quinidine, and propafenone.

The doctor may sometimes inject a sodium channel blocker into an intravenous drip. When the patient uses an oral form of the medication, he will usually begin taking the drug while he is still in the hospital. The doctor will typically prescribe a lower dosage of this medication initially, which he may increase or decrease on an as-needed basis. Patients should follow all dosage instructions carefully and should avoid abruptly discontinuing a medication of this kind, because this may cause abnormal heartbeats.

People taking a sodium channel blocker may experience some side effects, which should be reported to the prescribing physician if they become severe. The exact side effects will vary, depending on which specific medication was prescribed. Typically, a sodium channel blocker may cause dizziness, nausea, and vomiting, along with diarrhea or constipation. Loss of appetite, headache, and fatigue may occur, as well as anxiety, unusual taste in the mouth, and insomnia. Stomach cramps and tremors have also been reported.

More severe side effects require immediate medical care. Patients should be aware that a sodium channel blocker drug can cause chest pain, jaundice, and pain in the upper right area of the stomach. An irregular or pounding heartbeat, swelling of the extremities, and flu-like symptoms have also been reported. Some patients have reported a persistent cough that produced bloody mucus, and others have reported hearing changes or a ringing in the ears. Certain antiarrhythmic drugs, such as propafenone, may also infrequently result in fainting, wheezing, or sudden, unexplained weight gain.

The doctor may instruct the patient to take certain precautions while using a sodium channel blocker. Grapefruit, grapefruit juice, and similar products should be avoided, because these may interact with the drug. Patients should maintain their usual level of salt intake unless otherwise instructed by their doctors. Those who follow a strict vegan or vegetarian diet should inform the doctor. Some antiarrhythmics may be affected by the use of tobacco products.

Before taking a sodium channel blocker, patients must disclose their other medical conditions, medications, and supplements. Women who are pregnant or breastfeeding should discuss the potential risks with their doctors. These drugs may be contraindicated for use by those with a heart block, heart disease, or liver disease. Other medications may interact with these drugs, including antacids, sodium bicarbonate, and digoxin.