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| Class 1A | Class 1B | Class 1C | Class 2 | Class 3 | Class 4 | Class 5 |
Quinidine | Procainamide | Lidocaine | Mexiletine | Flecainide | Propafenone | Propranolol | Amiodarone | Sotalol | Ibutilide | Verapamil | Bretylium Tosylate |
Major indications |
| Serious ventricular arrhythmias, recurrent
PAT with WPW, atrial flutter, or fibrillation | Serious ventricular arrhythmias, PAT | Serious ventricular arrhythmias, digitalis-induced arrhythmias;
may decrease AV block | Oral treatment of serious recurrent ventricular arrhythmias | Refractory ventricular arrhythmias, slow conduction
in accessory pathways | Automatic junctional or atrial tachycardia,
SVT with accessory pathways | Serious supra- or ventricular arrhythmias; prevention of
SVT in WPW; slowing ventricular rate in atrial fibrillation | Any serious arrhythmia refractory to other therapies | Atrial and ventricular arrhythmias, particularly in
patients with structural heart disease | Conversion of atrial flutter or atrial fibrillation | SVT, but not with WPW; slowing ventricular
rate in atrial fibrillation | Main: reversion to VF after defibrillation |
Other: Serious ventricular arrhythmias |
Major contraindications |
| Known hypersensitivity to quinidine, myocardial depression,
sick sinus syndrome, impaired conduction, including complete AV
block, long QT | Myocardial depression, sick sinus syndrome, impaired conduction, including complete
AV block, long QT | | | Myocardial depression, serious structural heart disease | Myocardial depression | Asthma, hypoglycemia, AV block | Severe pulmonary disease | ↓ K+ and Mg2+ concentrations | Previously documented hypersensitivity | β-Adrenergic blockade; infants <1 year
old; myocardial depression | Postural hypertension |
Dose |
Oral | Sulfate: 30–60 mg/kg/d children,
10 mg/kg/d adults, divided 6h | 50–100 mg/kg/d divided q4h;
if slow-release form, q6h | | Children: 1.4–5.1 mg/kg/dose q8h | 50–200 mg/m2/d
div 12 h or 6.7–9.5 mg/kg/d div q12h | 300–400 mg/m2/d
div q6h | 2 mg/kg/d div q6h to start,
then up to 6 mg/kg/d | Loading 5–10 mg/kg/d
for 5–10 d, then 5 mg/kg/d qd | 2–8 mg/kg/d div
TID | NA | 4–7 mg/kg/d div
TID or QD or BID with slow-release forms | |
Gluconate: 20% higher does, every 8–12
h, 6 mg/kg every 2–4 h, 3–5 times daily | Adults: 450–1200 mg/d divided 8h |
IV | Not recommended | 10–15 mg/kg over 30–45 min, then
30–80 μg/kg/min | 1–2 mg/kg slowly, then 10–50 μg/kg/min infusion | | NA | | 0.01 mg/kg every 2 min to 0.1 mg/kg total | 5 mg/kg by central line over 30–60 min (diluted
in 5% DW); maintenance 10 mg/kg/d by
continuous infusion | | 0.01 mg/kg over 1 min, maximal dose 1 mg; can repeat 10
min after end of first infusion | 0.15 mg/kg over 1 min; can repeat in 30 min | 5 mg/kg, can repeat every 10–20 min to total
of 30 mg/kg |
Pharmacokinetics |
Therapeutic plasma levels (μg/mL) | 2–5 | 4–10 | 1.5–5 | 0.5–2 | 0.2–1 | <1 | 0.05–0.10 | 0.5–2 | ?<5 | Unknown | 0.1–0.3 | |
Side effects |
Cardiovascular | Myocardial depression, hypotension, prolonged AV conduction and
PR, QRS and QT durations (but may increase AV conduction by vagolytic action),
asystolic, ventricular flutter or fibrillation | Hypotension, prolonged AV conduction and PR, QRS, and QT
durations, AV block, asystole | Conduction abnormalities | | Myocardial depression, AV block (rare), makes ventricular arrhythmias worse, prolong PR,
QRS | Proarrhythmic in 2% of patients, myocardial depression,
prolonged PR, QRS, bradycardia | Myocardial depression, AV block | Severe bradycardia AV block; ventricular arrhythmias; makes heart
refractory to pacing | Torsades de points, bradycardia, myocardial depression | QT interval prolongation, proarrhythmia, esp. PVCs (5%),
VT (5%), Torsades de pointes and polymorphous VT (4%). Risk
higher with congestive heart failure, ↓ K+, ↓ Mg2+,
or history of torsades. Clinician must be prepared to perform DC cardioversion. | Myocardial depression; AV block; bradycardia | Postural hypotension |
Central nervous system | Tinnitus, confusion, seizures | Hallucinations, confusion | Seizures, ataxia, coma | Ataxia, tremor | Dizziness, headache, blurred vision | Dizziness, headache, tremor, taste disturbance | Lethargy, fatigue | Dizziness, ataxia | Lethargy, fatigue, dizziness | Headache (4%) | Dizziness | |
Gastrointestinal | Nausea, vomiting, diarrhea | Anorexia, nausea, vomiting | | GI upset, hepatitis | | Anorexia, nausea, vomiting, constipation | | GI upset, hepatitis | Nausea | Nausea (2%) | Nausea | Nausea, vomiting, parotid pain |
Hematologic | Thrombocytopenia | Agranulocytosis | | Blood dyscrasias | | | | | | | | |
Hypersensitivity | Fever, collapse, rash, respiratory arrest | SLE syndrome, fever, joint pains, rash | | | | | | | | | | |
Other | | | | | | | Bronchospasm, hypoglycemia | Skin discoloration and photosensitivity; corneal deposits; altered
thyroid function; pulmonary fibrosis | | | | |