Do not use Cordarone if:

• you are allergic to any ingredient in Cordarone , including iodine;
• you have complete, second degree, third degree, or severe sinoatrial heart block; an abnormally slow heartbeat; or shock due to serious heart problems; or if you have had fainting due to slow heartbeat (except if you have a pacemaker) ;
• you are taking cisapride, dofetilide, an H1 antagonist (eg, astemizole, loratadine, terfenadine), an HIV protease inhibitor (eg, ritonavir), a phosphodiesterase type 5 inhibitors (eg, vardenafil), or a streptogramin (eg, dalfopristin, quinupristin).

• Cordarone may cause dizziness, lightheadedness, or blurred vision. Do not drive, operate machinery, or do anything else that could be dangerous until you know how you react to Cordarone . Using Cordarone alone, with certain other medicines, or with alcohol may lessen your ability to drive or perform other potentially dangerous tasks.
• Long-term exposure to Cordarone may cause blue-gray discoloration of the skin, particularly of the face and hands. This effect is not harmful and usually reverses, sometimes incompletely, after the medicine is stopped. Avoiding prolonged exposure to the sun may help to prevent this effect.
• Limit alcoholic beverages while taking Cordarone .
• It may take several days to weeks for Cordarone to work. A response may not be seen for up to 3 weeks after the medicine is started.
• Cordarone stays in your body for weeks or months, even after you are no longer taking it. Therefore, caution is advised not only during treatment, but for several months after treatment with Cordarone has stopped if you are taking any interacting medicines.
• Cordarone may cause skin reactions similar to serious sunburn or sensitivity to sunlight. Avoid exposure to the sun, sunlamps, or tanning booths until you know how you react to Cordarone . Use a sunscreen or wear protective clothing if you must be outside for a prolonged period.
• Before you have any medical or dental treatments, emergency care, or surgery (including eye surgery to correct vision problems), tell the doctor or dentist that you are using Cordarone .
• Your doctor may want you to check your pulse rate every day while you take Cordarone . Learn how to monitor your pulse.
• Carry an identification card at all times that says you are taking Cordarone .
• Lab tests, including electrocardiogram (ECG), chest x-rays, lung tests, liver tests, thyroid tests, and eye exams, may be performed to monitor your progress. Be sure to keep all doctor and lab appointments.
• Use Cordarone with extreme caution in children. Safety and effectiveness have not been confirmed.
• Pregnancy and breast-feeding: Cordarone has been shown to cause harm to the fetus. If you think you may be pregnant, discuss with your doctor the benefits and risks of using Cordarone during pregnancy. Cordarone is excreted in breast milk. Do not breast-feed while taking Cordarone .

Check with your doctor if any of these most common side effects persist or become bothersome:

• abnormal skin sensations (loss of sensation; tingling; numbness; prickling); bitter taste in mouth; blue-green discoloring of skin (especially hands or feet); constipation; decreased sexual interest; dizziness; dry eyes; flushing of the face; general body discomfort; headache; involuntary muscle movements; loss of appetite; nausea; poor coordination; tiredness; trouble sleeping; vomiting.

• severe allergic reactions (rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); chest pain; chills, coldness; cough; coughing up blood; dark urine; decreased urination; easy bruising or bleeding; enlarged thyroid gland; eye discomfort; fatigue; fever; irregular pulse; loss of coordination; menstrual changes; muscle pain, tenderness, or weakness (especially with fever or unusual tiredness); nervousness; persistent sore throat; severe dizziness; severe stomach pain; shortness of breath; skin reaction similar to serious sunburn; slow heartbeat; sluggishness; sweating; tingling or numbness of hands or feet; uncontrolled shaking or tremor; unexplained weight change; vision changes (seeing halos, blurred vision, loss of vision); wheezing; worsening of irregular heartbeat; yellowing of the skin or eyes.

It is important to tell your doctor or pharmacist what medicines you are already taking, including those bought without a prescription and herbal medicines, before you start treatment with this medicine. Similarly, check with your doctor or pharmacist before taking any new medicines while taking this one, to ensure that the combination is safe.