Supraventricular and ventricular arrhythmias (Formulary)

AMIODARONE

Important: Therapy notes

MHRA advice: Amiodarone (Cordarone X): reminder of risks of treatment and need for patient monitoring and supervision (March 2022) (www.gov.uk).
Review therapy for patients in permanent atrial fibrillation on amiodarone for rate control only.

Monitoring amiodarone therapy

  • A chest x-ray is required prior to initiating therapy. During treatment, if pulmonary toxicity is suspected, repeat chest x-ray and test lung function.
  • Test liver and thyroid function (request TSH and FT4 and state patient is on amiodarone) prior to initiating therapy and every 6 months thereafter.
  • Development of cough or shortness of breath may indicate presence of serious pulmonary toxicity; new neurological symptoms may indicate development of neuropathy. Withdraw amiodarone immediately until further investigations can be carried out.
  • Most patients will develop reversible corneal microdeposits.  These tend to be benign, however a small number of patients will develop visual haloes and blurring of vision. Rarely optic neuritis can occur.  Recommend ophthalmological examination if blurred or decreased vision occurs.
  • Due to the high incidence of phototoxicity advise all patients to avoid exposure to sunlight and use a wide-spectrum sunscreen. Inform patients that photosensitivity may persist for several months after discontinuation of amiodarone.

Important: Formulation and dosage details

Formulation:

Tablets 100mg, 200mg (hospital use only)

Dosage:

By mouth, 400mg 3 times daily for 10 days, reduced to 200mg once daily or the minimum required to control the arrhythmia for usual maintenance. This loading dose is unlicensed in the UK but is recommended by Highland Consultant Cardiologists based on clinical experience and licensed doses in the US. 
Alternatively, follow the BNF recommendation.

Important: Formulation and dosage details

Formulation:

Concentrate for dilution and use as an intravenous infusion 150mg/3mL (hospital use only)

Dosage:

By intravenous infusion, irritant to veins and administration via PICC line preferred, initially 5mg/kg over 20 to 120 minutes with ECG monitoring; subsequent infusion given if necessary according to response up to maximum of 1·2 grams in 24 hours.

Important: Formulation and dosage details

Formulation:

Injection, prefilled syringe 300mg/10mL (hospital use only)

FLECAINIDE

Important: Therapy notes

Important: Formulation and dosage details

Formulation:

Tablets 50mg, 100mg (specialist initiation only)

Dosage:

Ventricular arrhythmias, by mouth, initially 100mg twice daily (maximum 400mg daily usually reserved for rapid control or in heavily-built patients), reduced after 3 to 5 days if possible.  

Supraventricular arrhythmias, 50mg twice daily, increased if required to maximum 300mg daily.

Important: Formulation and dosage details

Formulation:

Injection 150mg/15mL (hospital use only) unlicensed

Dosage:

Cardioversion of haemodynamically stable patients with normal left ventricular function in atrial fibrillation for less than 24 hours, by slow intravenous injection, bolus of 2mg/kg over 30 minutes maximum 150mg. To be carried out in hospital with ECG monitoring.

MEXILETINE

Important: Therapy notes

Important: Formulation and dosage details

Formulation:

Capsules 50mg, 100mg, 200mg (specialist initiation only)

PROPAFENONE

Important: Therapy notes

Important: Formulation and dosage details

Formulation:

Tablets 150mg (specialist initiation only)

Dosage:

150mg 3 times daily (maximum 300mg 3 times daily). Reduce dose if less than 70kg. 

RANOLAZINE

Important: Therapy notes

Important: Formulation and dosage details

Formulation:

Prolonged release tablets 375mg, 500mg and 750mg (specialist initiation only)

Dosage:

See SMC advice 565/09 .

Editorial Information

Document Id: F063