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 Propafenone.

Abnormal heart rhythms: Certain medications used to treat abnormal heart rhythms, including propafenone, may cause new abnormal heart rhythms or worsen existing ones. Your doctor will monitor you closely while you are taking propafenone. If you experience a fast, slow, or irregular heartbeat; fainting; heart palpitations; or dizziness while taking Propafenone, contact your doctor immediately.

Asthma or Bronchitis: Propafenone can worsen breathing problems for people with asthma or bronchitis. If you have asthma or other breathing disorders, discuss with your doctor how Propafenone may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Propafenone, and whether any special monitoring is needed.

Drowsiness/reduced alertness: Propafenone may cause blurred vision, dizziness, and fatigue. Do not drive or operate machinery until you know how Propafenone affects you.

Heart failure: Propafenone can cause or worsen heart failure and should not be used by people with severe or untreated heart failure. If you have heart failure and are taking Propafenone, 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 propafenone, contact your doctor immediately.

If you have a heart condition, discuss with your doctor how Propafenone may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Propafenone, and whether any special monitoring is needed.

Infection: Propafenone can reduce the number of cells that fight infection in the body (white blood cells). This usually occurs within 4 to 6 weeks of starting Propafenone. If you experience Fever, sore throat, fatigue, weakness, or a general feeling of being unwell while taking propafenone, contact your doctor immediately.

Kidney function: Kidney Disease or reduced kidney function may cause Propafenone to build up in the body, causing side effects. If you have reduced kidney function or kidney disease, discuss with your doctor how Propafenone may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Propafenone, and whether any special monitoring is needed.

Liver function: The liver removes most of Propafenone from the body. Liver disease or reduced liver function may cause Propafenone to build up in the body, causing side effects. If you have liver problems, discuss with your doctor how Propafenone may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Propafenone, and whether any special monitoring is needed. Your doctor may want to test your liver function regularly with blood tests while you are taking Propafenone.

If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Pregnancy: Propafenone should not be taken during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking Propafenone, contact your doctor immediately.

Breast-feeding: Propafenone passes into breast milk. If you are a breast-feeding mother and are taking propafenone, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of using Propafenone have not been established for children.

Seniors: Seniors may experience more dizziness while taking propafenone and may require lower doses.