SIDE EFFECTS: See also Warning section. Nausea or diarrhea may occur. If either of these effects persists or worsens, tell your doctor promptly. Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects. Tell your doctor right away if you have any serious side effects, including: symptoms of liver disease (such as persistent nausea/vomiting, loss of appetite, stomach/abdominal pain, yellowing eyes/skin, dark urine), symptoms of lung problems (such as persistent dry cough, shortness of breath), signs of kidney problems (such as change in the amount of urine). Get medical help right away if you have any very serious side effects, including: slow/fast/irregular heartbeat, severe dizziness, fainting. A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing. This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist. In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch. In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

PRECAUTIONS: See also Warning section. Before taking dronedarone, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details. Before using this medication, tell your doctor or pharmacist your medical history, especially of: liver disease, certain types of irregular heartbeat (second- or third-degree atrioventricular block or sick sinus syndrome, unless you have a heart pacemaker), serious side effects (such as liver/lung disease) from taking the medication amiodarone. Dronedarone may cause a condition that affects the heart rhythm (QT prolongation). QT prolongation can rarely cause serious (rarely fatal) fast/irregular heartbeat and other symptoms (such as severe dizziness, fainting) that need medical attention right away. The risk of QT prolongation may be increased if you have certain medical conditions or are taking other drugs that may cause QT prolongation. Before using dronedarone, tell your doctor or pharmacist of all the drugs you take and if you have any of the following conditions: certain heart problems (heart failure, slow heartbeat, QT prolongation in the EKG), family history of certain heart problems (QT prolongation in the EKG, sudden cardiac death). Low levels of potassium or magnesium in the blood may also increase your risk of QT prolongation. This risk may increase if you use certain drugs (such as diuretics/"water pills") or if you have conditions such as severe sweating, diarrhea, or vomiting. Talk to your doctor about using dronedarone safely. Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products). Older adults may be more sensitive to the side effects of this drug, especially QT prolongation (see above). This medication must not be used during pregnancy. It may harm an unborn baby. Discuss the use of reliable forms of birth control with your doctor. If you become pregnant or think you may be pregnant, tell your doctor right away. It is unknown if this medication passes into breast milk. Because of the possible risk to the infant, breast-feeding while using this drug is not recommended. Consult your doctor before breast-feeding.

DRUG INTERACTIONS: See also How to Use section. Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval. A product that may interact with this drug is: fingolimod. Many drugs besides dronedarone may affect the heart rhythm (QT prolongation). Examples include amiodarone, disopyramide, dofetilide, flecainide, pimozide, procainamide, propafenone, quinidine, sotalol, among others. Other medications can affect the removal of dronedarone from your body, which may affect how dronedarone works. Examples include azole antifungals (such as ketoconazole, itraconazole, voriconazole), cyclosporine, macrolide antibiotics (such as clarithromycin, erythromycin), nefazodone, HIV protease inhibitors (such as lopinavir, ritonavir), rifampin, St. John's wort, drugs used to treat seizures (such as carbamazepine, phenobarbital, phenytoin), telithromycin, among others. Dronedarone can slow down the removal of other medications from your body, which may affect how they work. Examples of affected drugs include dabigatran, digoxin, among others.

OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.