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Antiarrhythmic (Class III)

Amiodarone (IV — ICU/Peri-Arrest)

Brand names: Cordarone

Used in: Atrial Fibrillation

Amiodarone is an antiarrhythmic used for serious atrial and ventricular arrhythmias, including peri-arrest and intensive-care settings, when other options are unsuitable.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

US labelling (FDA)

Reference — US labelling, may differ from UK

Dosage must be individualized based on severity of arrhythmia and response. Use the lowest effective dose. Obtain baseline chest x-ray, pulmonary function tests, thyroid function tests, and liver aminotransferases. Correct hypokalemia, hypomagnesemia, and hypocalcemia before initiating treatment. Initiate treatment with a loading dose of 800 to 1600 mg/day until initial therapeutic response occurs (usually 1 to 3 weeks). Once adequate arrhythmia control is achieved, or if side effects become prominent, reduce Pacerone tablets dose to 600 to 800 mg/day for one month and then to the maintenance dose, usually 400 mg/day. ( 2 ) Recommended Dosage: Initiate treatment with a loading dose of 800 …

Source: US FDA prescribing information (openFDA / DailyMed), label dated 2024-02-02. Accessed 2026-06-12. US dosing and indications can differ from UK practice — use UK sources for prescribing decisions.

Clinical monograph

How it works

A predominantly class III antiarrhythmic (potassium-channel blockade prolonging repolarisation) with additional sodium, calcium and beta-blocking effects, slowing conduction and prolonging refractoriness.

Prescribing in practice

  • It has a very long half-life and extensive tissue accumulation, so effects and interactions persist for weeks after stopping.
  • Serious organ toxicities occur with longer use — thyroid (over- and under-active), pulmonary fibrosis, hepatotoxicity, corneal deposits, photosensitivity and skin discolouration.
  • Major interactions include warfarin and digoxin (reduce their doses) and other QT-prolonging drugs; give intravenous amiodarone via a central line where possible.

Monitoring

Baseline and periodic thyroid and liver function and a chest X-ray; review for visual, pulmonary or skin effects; monitor ECG (QT) and interacting-drug levels (INR, digoxin).

Counselling the patient

  • Use sun protection — it can make you burn easily and can discolour the skin.
  • Report breathlessness or cough, or symptoms of thyroid problems.
  • Mention it to clinicians for a long time after stopping, as it lingers and interacts.

Evidence & guidelines

Used for serious arrhythmias including peri-arrest (Resuscitation Council UK), reserved because of its toxicity profile.

Reference: Resuscitation Council UK ALS 2021; MHRA Amiodarone Safety Update; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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