Dronedarone belongs to the class of medications called antiarrhythmics. It is used to help control an abnormal heart rate and rhythm called atrial fibrillation and can lower the risk of having to go the hospital for heart problems or the risk of death. It works by affecting how electrical impulses affect the heart muscle. Dronedarone should only be used after other treatment options have been considered.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The usual recommended dose of this medication for adults is 400 mg twice daily with the morning and evening meal. People taking this medication should avoid drinking grapefruit juice or eating grapefruit, as this can increase the blood levels of this medication and lead to side effects and other problems.

Many things can affect the dose of a medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important that this medication be taken exactly as prescribed by your doctor. If you miss a dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication at room temperature in its original package and keep it out of the reach of children.

ASN-Dronedarone
Each white-to-off-white, film-coated, oblong-shaped tablet, debossed with "DRO" on one side and "400" on the other side, contains dronedarone hydrochloride equivalent to 400 mg of dronedarone. Nonmedicinal ingredients: colloidal silicon dioxide, crospovidone, hypromellose, lactose monohydrate, magnesium stearate, maize starch, poloxamer 407, and purified water; coating/polishing: isopropyl alcohol, methylene chloride, hypromellose, polyethylene glycol, and titanium dioxide.

Do not take dronedarone if you:

• are allergic to dronedarone or any ingredients of the medication
• are pregnant or breast-feeding
• are taking a medication such as ketoconazole, itraconazole, voriconazole, cyclosporin, telithromycin, clarithromycin,nefazodone, or ritonavir
• are taking a medication that can cause a change in heart rhythm called torsades de pointes (e.g., phenothiazines [promethazine, chlorpromazine], tricyclic antidepressants [amitriptyline, clomipramine, desipramine], flecainide, propafenone, quinidine, disopyramide, sotalol, amiodarone
• have a heart rate less than 50 beats per minute
• have a type of atrial fibrillation called permanent atrial fibrillation (where a decision has been made by the doctor not to try to change the heart rhythm back to normal)
• have an electrocardiogram (ECG) that shows a problem with the electrical activity of the heart called QT prolongation
• have second- or third-degree heart block or sick sinus syndrome (except if treated with a pacemaker)
• have severe congestive heart failure (CHF) or another condition associated with unstable heart function
• have severe left ventricular dysfunction
• have severely reduced liver function
• have liver or lung toxicity related to a prior use of the medication amiodarone

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent. The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• diarrhea
• heartburn
• nausea
• rash
• skin sensitivity to sunlight
• stomach pains
• taste changes
• tiredness
• vomiting
• weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• chest pain
• dizziness
• inflammation of the skin
• itchy, red skin
• signs of liver problems (e.g., yellow skin or eyes, abdominal pain, dark urine, clay-coloured stools, loss of appetite, nausea and vomiting, or itching)
• slow heart rate
• shortness of breath when lying down or sleeping
• swelling of the feet or lower legs
• sudden weight gain

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of an allergic reaction (e.g., difficulty breathing, coughing, or wheezing; hives; itchy skin rash)
• signs of angioedema (e.g., swelling of the face, lips, mouth, tongue or throat)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

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 this medication.

Congestive heart failure: If you have moderate congestive heart failure, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, 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 this medication 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 this medication, contact your doctor immediately.

Lung problems: 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 this medication.

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

Pregnancy: This medication should not be used during pregnancy. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if dronedarone passes into breast milk. This medication should not be used while breast-feeding.

Children: The safety and effectiveness of using this medication have not been established for children under 18 years of age.

There may be an interaction between dronedarone and any of the following:

• alfuzosin
• aliskiren
• amantadine
• amiodarone
• antihistamines (e.g., cetirizine, doxylamine, diphenhydramine, hydroxyzine, loratadine)
• antipsychotics (e.g., chlorpromazine, clozapine, haloperidol, olanzapine, quetiapine, risperidone)
• apixaban
• barbiturates (e.g., butalbital, pentobarbital phenobarbital)
• benzodiazepines (e.g., alprazolam, chlordiazepoxide, clonazepam, clorazepate, diazepam, flurazepam, midazolam)
• beta-blockers (e.g., atenolol, bisoprolol, metoprolol, propranolol)
• boceprevir
• bosentan
• buspirone
• bosutinib
• bromocriptine
• buprenorphine
• buserelin
• calcitriol
• calcium channel blockers (e.g., verapamil, diltiazem, nifedipine)
• cancer medications (e.g., busulfan, docetaxel, etoposide, imatinib, irinotecan, vinblastine, vincristine)
• captopril
• carbamazepine
• chloral hydrate
• chloroquine
• cinacalcet
• clonidine
• colchicine
•  inhaled corticosteroids (e.g., budesonide, ciclesonide, fluticasone)
• oral corticosteroids (e.g., methylprednisolone, prednisone)
• crizotinib
• cyclosporine
• dabigatran
• darifenacin
• deferasirox
• degarelix
• disopyramide
• digoxin
• domperidone
• donepezil
• doxazosin
• enzalutamide
• ergot alkaloids (e.g., ergotamine, dihydroergotamine)
• estrogens (e.g., conjugated estrogen, estradiol, ethinyl estradiol)
• famotidine
• fesoterodine
• fingolimod
• flecainide
• galantamine
• grapefruit juice and grapefruit
• guanfacine
• HIV non-nucleoside reverse transcriptase inhibitors (NNRTIs; e.g., delaviridine, efavirenz, etravirine, nevirapine)
• HIV protease inhibitors (e.g., atazanavir, indinavir, ritonavir, saquinavir)
• imatinib
• indacaterol
• indapamide
• ledipasvir
• leuprolide
• lidocaine
• lithium
• lomitapide
• loperamide
• macrolide antibiotics (e.g., clarithromycin, erythromycin, telithromycin)
• maraviroc
• mefloquine
• methadone
• methamphetamine
• metoclopramide
• metronidazole
• mifepristone
• mirabegron
• mitotane
• naloxegol
• narcotic pain relievers (e.g., codeine, fentanyl, morphine, oxycodone)
• nateglinide
• nefazodone
• nilotinib
• nitrates (e.g., isosorbide dintrate)
• octreotide
• olodaterol
• pasireotide
• phenobarbital
• phenytoin
• phosphodiesterase 5 inhibitors (e.g., sildenafil, tadalafil, vardenafil)
• pimecrolimus
• primaquine
• primidone
• procainamide
• propafenone
• prucalopride
• quinidine
• quinine
• quinolone antibiotics (e.g., ciprofloxacin, norfloxacin, ofloxacin)
• ranitidine
• rifabutin
• rifampin
• riociguat
• rivaroxaban
• rivastigmine
• romidepsin
• salmeterol
• saxagliptin
• selective serotonin reuptake inhibitors (SSRIs; e.g., citalopram, fluoxetine, paroxetine, sertraline)
• serotonin antagonists (anti-emetic medications; e.g., granisetron, ondansetron)
• sirolimus
• sitagliptin
• St. John's wort
• Solifenacin
• sofosbuvir
• "statin" medications (e.g., atorvastatin, lovastatin, simvastatin)
• sulfamethoxazole
• tacrolimus
• tamoxifen
• tamsulosin
• telaprevir
• theophylline
• tizanidine
• tolterodine
• tolvaptan
• tramadol
• trazodone
• tricyclic antidepressants (e.g., amitriptyline, clomipramine, imipramine, desipramine)
• trimethoprim
• ulipristal
• venlafaxine
• vilanterol
• warfarin
• zolpidem
• zopiclone

If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.

Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.