Cardiac arrest (VF/pulseless VT): Child: 5 mg/kg IV/IO after the third shock; repeat after the fifth shock. [VERIFY against current APLS guidance] Arrhythmia management in children: specialist advice only.
Amiodarone hydrochloride
Class III antiarrhythmic used in the treatment of shock-refractory cardiac arrest (VF/pulseless VT) and in the management of ventricular and supraventricular tachyarrhythmias when other treatments are ineffective or contraindicated.
Indications Preparations and Dose
Indication 1
Cardiac arrest: ventricular fibrillation or pulseless ventricular tachycardia refractory to defibrillation.
Patient Specific Considerations
Give by IV or IO bolus during cardiac arrest per Resuscitation Council UK ALS algorithm; hypotension and bradycardia are not limiting in the arrest setting. Correct hypokalaemia and hypomagnesaemia where identified.
Preparation
IV - Injection
Doses
Adult: 300 mg IV/IO bolus after the third shock; a further 150 mg IV/IO may be given after the fifth shock. [VERIFY - post-ROSC continuation infusion of 900 mg over 24 hours against current ALS guidance and local Role 1/2 capability]
Indication 2
Ventricular and supraventricular tachyarrhythmias, including atrial fibrillation, where other drugs are ineffective or contraindicated.
Patient Specific Considerations
Oral treatment should be initiated and titrated under specialist supervision only. Baseline and periodic monitoring required: thyroid function, liver function, serum potassium and chest X-ray. Not for routine initiation at Role 1.
Preparation
Oral - Tablet
Doses
Adult: 200 mg three times daily for 1 week, then 200 mg twice daily for 1 week, then 200 mg once daily as maintenance (or the minimum effective dose).
Preparation Guidance
For IV use dilute in glucose 5% only - incompatible with sodium chloride 0.9%. In cardiac arrest give as bolus (pre-filled syringe where available, or diluted in glucose 5% to 20 mL) followed by a flush. Infusions should be given via a central line where possible; concentrations above 2 mg/mL cause phlebitis in peripheral veins. Do not mix with other drugs in the same line.
Legal status / who can administer
POM
Doctors, Paramedics
Major contraindications
In cardiac arrest there are no absolute contraindications. Outside the arrest setting: sinus bradycardia; sino-atrial heart block; severe conduction disturbances or sinus node disease (unless pacemaker fitted); thyroid dysfunction; known iodine hypersensitivity; severe hypotension or circulatory collapse.
Cautions
Elderly (conduction disturbance); heart failure; hypokalaemia (correct before use outside arrest); photosensitivity (advise sun protection); pulmonary toxicity (new or worsening dyspnoea/cough); corneal microdeposits; thyroid disease; very long half-life (approximately 50 days) - effects and interactions persist for weeks to months after stopping.
Avoid: present in milk in significant amounts; risk of neonatal thyroid dysfunction due to iodine content.
Avoid unless there is no alternative: risk of neonatal goitre and thyroid dysfunction; use in cardiac arrest is not withheld on grounds of pregnancy.
Elimination is not primarily hepatic-dependent but hepatotoxicity is recognised: monitor liver function; avoid ongoing therapy in severe impairment. [VERIFY - BNF/SPC]
Raises plasma concentration of digoxin (halve digoxin dose) and enhances the effect of warfarin (monitor INR). Increased risk of ventricular arrhythmia with other QT-prolonging drugs (e.g. quinolones, macrolides, antipsychotics, antimalarials). Increased risk of bradycardia, AV block and myocardial depression with beta-blockers and rate-limiting calcium-channel blockers. Grapefruit juice raises plasma concentration. Interactions persist long after discontinuation due to prolonged half-life.
Lidocaine (shock-refractory VF/pulseless VT where amiodarone is unavailable). [VERIFY - local formulary alternative]
Not compatible with flying duties: both the underlying arrhythmia and the adverse-effect profile (visual, thyroid, pulmonary) are disqualifying; occupational medical review required. [VERIFY against JSP 950 aeromedical standards]
Unfit to dive: underlying arrhythmia is disqualifying for diving duties; refer for occupational medical assessment. [VERIFY against JSP 950 diving standards]
Overdose: bradycardia, hypotension, QT prolongation and ventricular arrhythmia may occur; management is supportive - consult TOXBASE and the National Poisons Information Service. Note the very long elimination half-life when assessing duration of monitoring.