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 Multaq (Dronedarone).

Congestive heart failure: If you have moderate congestive heart failure, discuss with your doctor how Multaq (Dronedarone) may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Multaq (Dronedarone), and whether any special monitoring is needed. This medication should not be used for people with severe congestive heart failure. People with severe heart failure who take Multaq (Dronedarone) have an increased chance of dying. If you develop heart failure symptoms or worsening symptoms (e.g., weight gain, increasing shortness of breath, difficulty breathing at night, swelling of the feet or legs) while taking Multaq (Dronedarone), contact your doctor immediately.

Lung problems: Multaq (Dronedarone) can cause lung problems (Pulmonary Fibrosis, inflammation of lung tissue). Tell your doctor immediately if you experience any difficulty breathing, shortness of breath, or Dry Cough while you are taking Multaq (Dronedarone).

Kidney function: The results of a blood test for kidney function, called creatinine, may be increased without a change in your kidney function. Your doctor will use the creatinine level as your new normal. Tell any other doctor you see about the new "normal" value of your blood creatinine.

Liver: There have been reports of liver injury in people who were taking Multaq (Dronedarone). Your doctor may regularly perform tests to monitor your liver function. If you experience symptoms of liver damage (e.g., yellowing of the skin or eyes, fatigue, abdominal pain, nausea, vomiting, dark urine, or itching), contact your doctor immediately.

Low potassium and magnesium levels: Before starting and while taking Multaq (Dronedarone), your doctor may want to check your blood levels of potassium and magnesium, especially if you are taking medications (e.g., Hydrochlorothiazide, Furosemide, Indapamide) that may reduce these levels. If they are low, your doctor may recommend that you take supplements or may make changes to your medications.

QT prolongation: Multaq (Dronedarone) can affect the electrical activity of the heart and cause QT prolongation. You doctor will monitor your heart rhythm regularly while you are taking Multaq (Dronedarone) with a test called an electrocardiogram (ECG). You should not take Multaq (Dronedarone) if your ECG already shows that you have QT prolongation or if you are taking a medication that can cause QT prolongation.

Pregnancy: Multaq (Dronedarone) should not be used during pregnancy. If you become pregnant while taking Multaq (Dronedarone), contact your doctor immediately.

Breast-feeding: It is not known if Multaq (Dronedarone) passes into breast milk. Multaq (Dronedarone) should not be used while breast-feeding.

Children: The safety and effectiveness of using Multaq (Dronedarone) have not been established for children under 18 years of age.