Before you begin using a medication, be sure to inform your doctor of any medical conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Mexiletine.
Abnormal heart rhythms: Certain medications used to treat abnormal heart rhythms, including mexiletine, may cause new abnormal heart rhythms or worsen existing ones. Your doctor will monitor you closely while you are taking mexiletine. If you experience a fast, slow, or irregular heartbeat; fainting; heart palpitations; or dizziness while taking Mexiletine, contact your doctor immediately.
Blood clotting: Mexiletine can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. Tell your doctor about any signs that your blood is not clotting as quickly as usual. Such symptoms may include black and tarry stools, blood in the urine, easy bruising, or cuts that won't stop bleeding.
Dizziness, tremor, and coordination: Mexiletine may cause dizziness, tremor, or changes in coordination. Do not drive or operate machinery until you know how Mexiletine affects you.
Drug Reactions with Eosinophilia and Systemic Symptoms (DRESS): DRESS is a type of allergic reaction that can affect multiple organs. Early symptoms often include fever, rash on the face or upper body, and swelling of the face. In severe cases, organs such as the kidney or liver can become inflamed and function decreases. If you experience unusual symptoms, contact your doctor as soon as possible.
Heart failure: Mexiletine can cause or worsen heart failure. If you have heart failure and are taking Mexiletine, your doctor will monitor you closely during treatment. If you notice shortness of breath; weight gain; or swelling in the hands, feet, or lower legs while taking mexiletine, contact your doctor immediately.
Infection: Mexiletine can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people who have contagious infections. Tell your doctor immediately if you begin to notice the signs of an infection such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.
Liver problems: Liver disease or reduced liver function may cause Mexiletine to build up in the body, causing side effects. Mexiletine can cause liver problems. Your doctor will monitor your liver function while you are taking Mexiletine. If you experience nausea, abdominal pain, yellowing of the skin or eyes, pale stools, or dark urine while taking mexiletine, contact your doctor immediately. People with liver problems should discuss with their doctor how Mexiletine may affect their medical condition, how their medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.
Low Blood Pressure: Mexiletine may cause or worsen low blood pressure. Tell your doctor if you experience symptoms of severely decreased blood pressure, such as weakness or dizziness, particularly when rising suddenly from a sitting or lying position. If you have low blood pressure, discuss with your doctor how Mexiletine may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.
Seizures: People with a history of seizures should discuss with their doctor how Mexiletine may affect their medical condition, how their medical condition may affect the dosing and effectiveness of Mexiletine, and whether any special monitoring is needed.
Pregnancy: Mexiletine should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Mexiletine, contact your doctor immediately.
Breast-feeding: Mexiletine passes into breast milk. If you are a breast-feeding mother and are taking mexiletine, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using Mexiletine have not been established for children.
