Amiodarone

💊 What is Amiodarone used for?

• •The label says this injection is used to start treatment and prevent frequently recurring ventricular fibrillation (a dangerous, chaotic heart rhythm from the lower heart chambers) and hemodynamically unstable ventricular tachycardia (a fast heart rhythm from the lower chambers that is causing poor blood flow), in patients who have not responded to other therapy. It can also be used in people who are supposed to take oral amiodarone but cannot swallow medicine. The label says it is meant for acute treatment until the heart rhythm is stable. Most patients need this therapy for 48 to 96 hours, but it may be given longer if needed. Patients may be moved to oral amiodarone during or after treatment.

How it works

The label describes amiodarone as a class III antiarrhythmic drug. It is meant to help bring the heart rhythm back under control. The label does not describe the exact mechanism in more detail.

How it is usually taken

• •This medicine is given by a healthcare team through a vein. The label says it must be delivered using a volumetric infusion pump, ideally through a central venous catheter that is used only for this medicine, and with an in-line filter. The label explains that the starting dose is given over the first 24 hours in stages, and that the rate is adjusted closely based on how the patient responds. The label says the infusion should be given slowly, and the rate should not be pushed above the recommended limits. Blood pressure, heart rate, and other signs are monitored closely during treatment.

Comes as

• •Injection, 50 mg/mL
• •150 mg/3 mL single-dose glass vial
• •450 mg/9 mL single-dose glass vial
• •900 mg/18 mL single-dose glass vial

⚠️ Amiodarone side effects

🛑 Who should not take Amiodarone, and who should be careful

The label says not to take it if

• 🚨You are allergic to amiodarone or any of its ingredients, including iodine.
• 🚨You have cardiogenic shock.
• 🚨You have marked sinus bradycardia (a very slow heart rate).
• 🚨You have second- or third-degree atrioventricular (AV) block, unless a working pacemaker is available.

Tell your doctor before taking it if

• •The label says this medicine should be given only by doctors who are experienced in treating life-threatening arrhythmias and who can closely monitor its effects.
• •Tell your care team about any heart rhythm problems, liver problems, or thyroid problems, including any history of slow heart rate or heart block.
• •Tell your care team about all medicines, supplements, and herbs you take, including St. John's Wort and over-the-counter cough medicines that contain dextromethorphan.
• •The label says baseline liver enzyme abnormalities are not a reason to avoid treatment, but they are watched closely.
• •The label notes that effects can last after the medicine is stopped because amiodarone has a long half-life.

🔀 Amiodarone with other medicines, food and alcohol

The label says to discuss these with your doctor or pharmacist

• •Other medicines that prolong the QT interval, such as some antiarrhythmics, lithium, certain antibiotics, azole antifungals, and tricyclic antidepressants. The label says these increase the risk of torsade de pointes, and it generally advises avoiding them together.
• •Medicines that slow the heart rate, such as digoxin, beta blockers, verapamil, diltiazem, ivabradine, and clonidine. The label says heart rate should be monitored when these are used together.
• •Quinidine, procainamide, and flecainide, because amiodarone can slow how the body breaks them down. The label says added antiarrhythmics are usually started at a lower dose.
• •Grapefruit juice, which the label says significantly increases amiodarone levels. Patients are advised to avoid it.
• •St. John's Wort, which can affect amiodarone levels. Patients are advised to avoid it.
• •Over-the-counter cough medicines that contain dextromethorphan, which the label says to avoid.
• •Protease inhibitors and certain antibiotics and antifungals, which can change amiodarone levels.
• •Corneal refractive laser surgery, which most device makers contraindicate in patients taking amiodarone.

Alcohol and food

The label specifically says to avoid grapefruit juice while taking amiodarone because it significantly increases drug levels. The label does not give guidance about alcohol.

🤰 Amiodarone in pregnancy and breastfeeding

Pregnancy

The label says amiodarone and its metabolite cross the placenta. Reported risks include slow heart rate and QT prolongation in newborns, thyroid problems in newborns, developmental problems, slow fetal growth, and premature birth. Animal studies showed harm to developing babies and maternal deaths at some doses. The label does not describe a full risk-benefit decision for pregnancy beyond these findings.

Breastfeeding

The label says amiodarone and its metabolite are passed into human milk, and that breast-feeding could expose the nursing infant to a significant dose. The label advises the mother to stop nursing while being treated with amiodarone.

🗓️ Storage, missed doses and taking too much

Storage

The label says to store the vials at 20° to 25°C (68° to 77°F). Protect from light and excessive heat, and keep the vial in its carton until used to protect it from light. Discard any unused portion. The label notes the stoppers are not made with natural rubber latex.

If a dose is missed

The label does not say.

If too much is taken

The label says there have been cases of amiodarone overdose, some fatal. Effects of an inadvertent overdose of the IV medicine include low blood pressure, cardiogenic shock, slow heart rate, AV block, and liver toxicity. Treatment may include slowing the infusion, vasopressor drugs, positive inotropic agents, volume expansion, and temporary pacing. Liver enzymes are monitored closely. The label says neither amiodarone nor its metabolite can be removed by dialysis.

🗒️ Questions to ask about Amiodarone

• What is the reason I need amiodarone instead of another heart rhythm medicine?
• How will you watch my blood pressure and heart rate while I receive this medicine?
• How often will my liver tests be checked, and what results would change the plan?
• Am I at risk for thyroid problems, and what symptoms should I watch for?
• Which of my current medicines or supplements could interact with amiodarone?
• How long do the effects of amiodarone last after treatment stops?
• If I need to switch to oral amiodarone, what should I know about it?

❓ Amiodarone: frequently asked questions