Amiodarone (Pacerone) is an antiarrhythmic medication. It's FDA-approved to treat life-threatening ventricular fibrillation and fast heart rate (tachycardia) in adults who either can't take it or whose condition isn't well-controlled by other antiarrhythmics. It's sometimes prescribed off-label for atrial fibrillation (AFib). Amiodarone (Pacerone) comes as tablets that are taken by mouth. The total daily dose can be taken once per day, or split into smaller doses and taken throughout the day to prevent stomach-related side effects, like nausea and vomiting.
Life-threatening ventricular fibrillation that keeps coming back (when other antiarrhythmics haven't worked well)
Life-threatening tachycardia that keeps coming back (when other antiarrhythmics haven't worked)
Amiodarone (Pacerone) is a class III antiarrhythmic medication. It mainly works by blocking potassium channels in the heart. This slows down the electrical activity in the heart and stabilizes heart rhythm.
Source: DailyMed
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
More common
dizziness, lightheadedness, or fainting
fever (slight)
numbness or tingling in the fingers or toes
painful breathing
sensitivity of the skin to sunlight
trembling or shaking of the hands
trouble with walking
unusual and uncontrolled movements of the body
weakness of the arms or legs
Less common
Blue-gray coloring of the skin on the face, neck, and arms
blurred vision or blue-green halos seen around objects
coldness
dry, puffy skin
fast or irregular heartbeat
nervousness
pain and swelling in the scrotum
sensitivity of the eyes to light
sensitivity to heat
slow heartbeat
sweating
swelling of the feet or lower legs
trouble with sleeping
unusual tiredness
weight gain or loss
Rare
Skin rash
yellow eyes or skin
Incidence not known
Agitation
back, leg, or stomach pains
bleeding gums
blistering, peeling, or loosening of the skin
blood in the urine
bloody, black, or tarry stools
blue lips, fingernails, or skin
blurred or double vision
chills
clay-colored stools
confusion
confusion as to time, place, or person
coughing or spitting up blood
cracks in the skin
dark urine
decreased awareness or responsiveness
decreased urine output
difficult or labored breathing
difficult urination
fast heartbeat
general body swelling
high fever
holding false beliefs that cannot be change by facts
hostility
inability to have or keep an erection
indigestion
irregular, fast or slow, or shallow breathing
irritability
joint or muscle pain
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or genitals
loss in sexual ability, desire, drive, or performance
loss of consciousness
loss of heat from the body
lower back or side pain
mood or mental change
muscle cramps, spasms, twitching, pain, or stiffness
no breathing
noisy breathing
nosebleeds
pain in the abdomen, groin, or scrotum
pain or burning with urination
pains in the stomach, side, or abdomen, possibly radiating to the back
pale skin
pinpoint red spots on the skin
rapid weight gain
red skin lesions, often with a purple center
red, irritated eyes
red, swollen skin
seeing, hearing, or feeling things that are not there
seizures
severe headache
severe sleepiness
sores, ulcers, or white spots on the lips or in mouth
stomach pain
swelling of the face, ankles, or hands
swelling of the scrotum
swollen or painful glands
tightness in the chest
troubled breathing
unpleasant breath odor
unusual bleeding or bruising
unusual drowsiness, dullness, tiredness, weakness or feeling of sluggishness
unusual excitement, nervousness, or restlessness
vomiting of blood
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
Less common
Bitter or metallic taste
decrease in sexual interest
decreased sexual ability in males
feeling of warmth
redness of the face, neck, arms and occasionally, upper chest
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Works well to treat certain heart rate and rhythm problems
Can be taken with or without food
Can be taken once daily (as long as you're tolerating the medication and the total daily dose is less than 1,000 mg)
Stays in the body for many weeks
Not for people with iodine allergy
Only available as a 200 mg tablet, so you might need to take several tablets depending on your dose
Your cardiologist will likely order blood work or other tests before you start and while you're taking amiodarone (Pacerone). These include electrocardiogram (ECG), liver enzyme levels, and thyroid function tests. These tests help your cardiologist see how well amiodarone (Pacerone) is working and if it's causing serious side effects.
When you're starting oral amiodarone (Pacerone), your cardiologist will prescribe a higher dose for several weeks for the medication to build up in your body. Let your healthcare team know if you're experiencing any side effects during this time, like nausea or vomiting. If so, they might lower your dose of amiodarone (Pacerone) or split your total daily dose into smaller doses to take throughout the day.
Amiodarone (Pacerone) can cause skin sensitivity to the sun. To protect your skin, make sure to wear sunscreen when going outside, wear long-sleeve clothing, and limit exposure to sunlight.
If you and your cardiologist decide to stop amiodarone (Pacerone), this medication can still last in the body for many weeks. This means that you're still at risk for side effects and medication interactions for weeks after your dose.
Avoid grapefruit or grapefruit juice while taking amiodarone (Pacerone) because it can raise the amount of the medication in your body, which raises your risk of side effects.
Amiodarone (Pacerone) can interact with many medications. For example, it can raise the risk of bleeding if you take it with warfarin (Coumadin). It can also raise the risk of dangerously slow heart rate if you take it with antiviral medications containing sofosbuvir. Tell your care team about all the medications you're taking before you start amiodarone (Pacerone) so they can help you check for interactions.
Don't take amiodarone (Pacerone) during pregnancy because it can cause harm to growing babies. Let your healthcare team know if you're pregnant or want to become pregnant and they can let you know about safer treatment options.
You're recommended to avoid breastfeeding while you're taking amiodarone (Pacerone) because this medication can pass into breastmilk and might harm a nursing infant. If you're nursing, your healthcare team might recommend using baby formula instead.
Because amiodarone (Pacerone) stays in your system for several weeks after your last dose, check with your cardiologist or obstetrician-gynecologist (OB-GYN) when it's safe to breastfeed after stopping the medication.
Amiodarone (Pacerone) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Risk factors: Low levels of potassium, magnesium, or calcium | Taking medications that affect electrolyte levels, including diuretics (water pills), laxatives (for constipation), or corticosteroids | Diarrhea that lasts a long time
Rarely, amiodarone (Pacerone) can cause or worsen arrhythmias (abnormal heartbeat), which can be life-threatening. You should only take this medication if you have a serious heart condition, and if you're able to follow-up with your cardiologist regularly to monitor your heart health. To lower your risk of serious heart rhythm problems, your care team will check that your electrolyte levels are balanced before you start this medication. They might also order an electrocardiogram (ECG) (test of your heart's electrical activity) on a regular basis to make sure the amiodarone (Pacerone) is working as it should. If you ever experience chest discomfort, dizziness, fainting, or fast heartbeat while you are taking amiodarone (Pacerone), get medical help right away.
Amiodarone (Pacerone) can cause inflammation in the lungs that leads to serious damage. This can be life-threatening. You'll likely get a chest x-ray before you start this medication, then every 3 to 6 months. Seek medical help immediately if you experience a cough, shortness of breath, wheezing, or chest tightness that doesn't go away or gets worse with time. You might need to be treated with oral steroids.
Though rare, amiodarone (Pacerone) can cause liver damage, which can be life-threatening. Your prescriber will check your liver enzyme level before and during treatment to make sure your liver is healthy. If your liver enzyme level is too high, your cardiologist might lower your dose or ask you to stop taking amiodarone (Pacerone). Let your care team know if you're taking other medications that can damage your liver. If you notice severe nausea, vomiting, right-sided stomach pain, fatigue, low or no appetite, or yellowing of the skin or eyes, get medical help right away.
Though rare, amiodarone (Pacerone) can cause serious vision problems, including permanent blindness. This side effect has been reported as early as 10 days after starting this medication. You should get regular eye exams while you are on amiodarone (Pacerone). Call your optometrist (eye specialist) right away if you notice a change in your vision, including blurriness, trouble seeing things to the side, or halos.
Risk factors: History of thyroid problems, including nodules or goiter
Amiodarone (Pacerone) can affect your thyroid hormone levels and cause either low or high hormone levels. High thyroid levels (hyperthyroidism) can cause an arrhythmia, which can be dangerous. Your prescriber will check your thyroid function tests regularly throughout treatment with amiodarone (Pacerone).
Risk factors: Abnormal electrolyte levels | Taking other medications that slow the heartbeat | Taking certain hepatitis C medications
Amiodarone (Pacerone) can cause your heartbeat to become too slow or even have unusual pauses. In some rare cases, people have needed a pacemaker to keep their heart beating normally. Taking certain medications at the same time, including some hepatitis C antivirals (e.g., sofosbuvir, Harvoni (ledipasvir/sofosbuvir)) might raise the risk of this side effect. If you experience symptoms of slow heart rate, such as dizziness or feeling like you're going to pass out, get medical help right away.
Risk factors: Have a heart device like a pacemaker
Taking amiodarone (Pacerone) long-term can affect the function of heart devices like defibrillators or pacemakers. Make sure that you get regular checkups to make sure your device is adjusted appropriately while you're taking amiodarone (Pacerone).
Amiodarone (Pacerone) can cause harm to unborn babies if taken by mothers during pregnancy. If you're able to become pregnant, your healthcare team might ask you to take a pregnancy test to confirm you're not pregnant before you can start amiodarone (Pacerone). You're recommended to use effective birth control during treatment with amiodarone (Pacerone).
Taking amiodarone (Pacerone) can cause nerve problems (neuropathy), such as tingling, numbness, and pain in your legs and feet. There's a risk that neuropathy won't go away after you stop taking amiodarone (Pacerone). Tell your prescriber if you notice these symptoms.
Adults:
Loading dose: The typical starting dose ranges from 800 mg to 1,600 mg by mouth daily for 1 to 3 weeks. Once your heart rhythm becomes stable (or if the side effects become too bothersome), your cardiology team will lower the dose to 600 mg to 800 mg daily for a month.
Maintenance dose: The typical maintenance dose is 400 mg by mouth daily.
Using this medicine with any of the following medicines is not recommended. Your doctor may decide not to treat you with this medication or change some of the other medicines you take.
Using this medicine with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Using this medicine with any of the following medicines may cause an increased risk of certain side effects, but using both drugs may be the best treatment for you. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.
Second- or third-degree heart block
Low heart rate without a pacemaker
Severe allergy to iodine
Life-threatening ventricular fibrillation that keeps coming back (when other antiarrhythmics haven't worked well)
Life-threatening tachycardia that keeps coming back (when other antiarrhythmics haven't worked)
Ventricular arrhythmias (a type of irregular heart rhythm)
Prevention of atrial fibrillation (Afib) or atrial flutter
Prevention of paroxysmal supraventricular tachycardia (PSVT) - immediate-release tablets only
Treatment of life-threatening ventricular arrhythmias - immediate-release tablets only
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Chokesuwattanaskul, R., et al. (2020). Low-dose amiodarone is safe: A systematic review and meta-analysis. The Journal of Innovations in Cardiac Rhythm Management.
Connolly, S. J., et al. (1999). Evidence-based analysis of amiodarone efficacy and safety. Circulation.
Florek, J. B., et al. (2023). Amiodarone. StatPearls.
Harris, L., et al. (1983). Side effects of long-term amiodarone therapy. Circulation.
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