Category:

• Miscellaneous

Description:

• Antidysrhythmic (Class IA), antimalarial

Indications:

• PO: PVC’s, ventricular tachycardia (when not associated with complete heart block), junctional (nodal) dysrhythmias, AV junctional premature complexes, paroxysmal junctional tachycardia, premature atrial contractions, paroxysmal atrial tachycardia, atrial flutter, atrial fibrillation (chronic and paroxysmal)

• IM/IV: when PO therapy not feasible or when rapid therapeutic effect is required, life threatening Plasmodium falciparum malaria

Contraindications:

• Digitalis intoxication manifested by AV conduction disorders, complete AV block with an AV nodal or idioventricular pacemaker, left bundle branch block, or other severe intraventicular condition defects with marked QRS widening, ectopic impulses, and abnormal rhythms due to escape mechanisms, history of drug-induced torsade de pointes, history of long QT syndrome, myasthenia gravis

Precautions:

• Pregnancy category C; use during pregnancy considered safe for the fetus; high doses can produce oxytocic properties and potential for abortion; excreted in breast milk; compatible with breast feeding

• Treatment of atrial flutter without prior medication to control ventricular rate

• Marginally compensated cardiovascular disease, incomplete AV block

• Digitalis intoxication, hyperkalemia, renal, or hepatic insufficiency

Adverse Reactions (Side Effects):

• CNS: apprehension, ataxia, confusion, delirium, dementia, depression, dizziness, excitement, fever, headache, vertigo

• CV: angioedema, arterial embolism, bradycardia, complete AV block, hypotension, prolonged QT interval, syncope, torsade de pointes, ventricular extrasystoles, ventricular flutter, ventricular tachycardia and fibrillation, widening of the QRS complex

• EENT: disturbed hearing, disturbed vision, optic neuritis, reduced visual field

• GI: abdominal pain, diarrhea, esophagitis, hepatotoxicity, nausea, vomiting

• HEME: acute hemolytic anemia, agranulocytosis, leukocytosis, neutropenia, thrombocytopenic purpura

• MS: arthralgia, increase in serum skeletal muscle creatine phosphokinase, myalgia

• SKIN: abnormalities of pigmentation, cutaneous flushing with intense pruritus, eczema, exfoliative eruptions, photosensitivity, psoriasis, purpura, rash, urticaria, vasculitis

• MISC: cinchonism, lupus nephritis, positive ANA, systemic lupus erythematosus

Dosage:

Administered orally

• Adult:   Give 200mg test dose PO/IM (gluconate) several hours before full dosage to determine possibility of idiosyncratic reaction: PO 10-600mg every 4-6 hours, initiate at 200 mg/dose and adjust dose to maintain desired therapeutic effect, max 3-4g daily; SUS REL 300-600mg every 8-12 hours;

• Child:   Give 2 mg/kg test dose PO/IM (gluconate) several hours before full dosage to determine possibility of idiosyncratic reaction: PO 15-60 mg/kg/day divided into 4-5 doses or 6 mg/kg every 4-6 hours; usual 30 mg/kg/day or 900mg per square meter daily given in 5 divided doses