C H A P T E R 4 5
Antiarrhythmic agents
703
TABLE 45.1
DRUGS IN FOCUS Antiarrhythmic agents (continued)
Drug name
Dosage/route
Usual indications
Class I antiarrhythmics (continued)
Class Ib
lignocaine (Xylocaine)
Adult: 300 mg of 10% solution IM; 50- to
100-mg IV bolus at the rate of 20–50 mg/
minute; 1- to 4-mg/minute IV infusion
Paediatric: safety and efficacy not established;
1 mg/kg IV followed by IV infusion 30 mcg/kg
per minute has been recommended
Treatment of life-threatening ventricular
arrhythmias during myocardial infarction
or cardiac surgery; also used as
bolus injection in emergencies when
monitoring is not available to document
exact arrhythmia
Class Ic
flecainide (Flecatab,
Tambocor)
50–100 mg PO q 12 hours; reduce dose as
needed with older people or people with
renal impairment
Treatment of life-threatening ventricular
arrhythmias in adults; prevention of
paroxysmal atrial tachycardia (PAT) in
symptomatic people with no structural
heart defect
propafenone (Rytmonorm)
150–300 mg PO based on the individual’s
response; start with lower dose and increase
slowly with older people
Treatment of life-threatening ventricular
arrhythmias in adults; prevention of PAT
in symptomatic people with no structural
heart defect
Class II antiarrhythmics
esmolol (Brevibloc)
Loading dose of 500 mcg/kg per minute IV,
then 50 mcg/kg per minute for 4 minutes,
maintain with IV infusion 100 mcg/kg per
minute
Short-term management of
supraventricular tachycardia in adults
and tachycardia that is not responding to
other measures
propranolol (Inderal,
Deralin)
10–30 mg PO t.d.s. to q.i.d.
Treatment of supraventricular tachycardias
caused by digoxin or catecholamines in
adults; also used as an antihypertensive,
antianginal and antimigraine headache drug
Class III antiarrhythmics
amiodarone (Aratac,
Cordarone X,
Cardinorm)
800–1,600 mg/day PO in divided doses for
1–3 weeks, then 600–800 mg/day PO for
1 month, reduce to 400 mg/day PO if rhythm
is stable 1,000 mg IV over 24 hours; then
540 mg IV at 0.5 mg/minute for 18–96 hours
Treatment of adults with life-threatening
ventricular arrhythmias not responding to
any other drug; preferred antiarrhythmic
in Advanced Cardiac Life Support
protocol
sotalol (Cardol, Sotacor)
80 mg/day PO, may be titrated to
240–320 mg/day PO; reduce dose in
people with renal impairment
Treatment of adults with life-threatening
ventricular arrhythmias not responding to
any other drug
Class IV antiarrhythmics
diltiazem (Cardizem)
30 mg PO q.i.d. before meals and at bedtime,
increased to maximum 360 mg/day PO
IV to treat paroxysmal supraventricular
tachycardia in adults
verapamil (Anpec,
Cordilox SR, Isoptin)
Adult: 5–10 mg IV over 2 minutes, may repeat
with 10 mg in 30 minutes if needed
Paediatric: 0.1–0.3 mg/kg IV over 2 minutes,
do not exceed 5 mg per dose; may repeat in
30 minutes if needed
IV to treat paroxysmal supraventricular
tachycardia; temporarily controls the
ventricular response to rapid atrial rates
Other antiarrhythmics
adenosine (Adenocor,
Adenoscan)
6 mg IV as a rapid bolus over 1–2 seconds;
may repeat with 12-mg IV bolus after
1–2 minutes if needed, may be repeated a
second time if needed
Treatment of supraventricular tachycardias,
including those caused by the use of
alternative conduction pathways in adults
digoxin (Lanoxin)
Adult: 0.75- to 1.25-mg PO loading dose, then
0.125–0.25 mg/day PO or 0.125- to 0.25-mg IV
loading dose, and then 0.125–0.25 mg/day PO
Paediatric: 10- to 50-mcg/kg loading dose PO
or 8- to 50-mcg/kg loading dose IV, based on
age; then maintenance dose of 25%–35% of
loading dose
Treatment of atrial flutter, atrial fibrillation,
paroxysmal atrial tachycardia
