Vaughan williams classification

Class Ia

Uses: APB and VPB suppression, SVT and VT suppression, AF or atrial flutter, and VF suppression

Disopyramide

IV: Initially, 1.5 mg/kg over > 5 minutes followed by an infusion of 0.4 mg/kg/hour

Oral immediate-release: 100 or 150 mg every 6 hours

Oral controlled-release: 200 or 300 mg every 12 hours

2–7.0 mcg/mL (5.9–20.6 mcmol/L)

Anticholinergic effects (urinary retention, glaucoma, dry mouth, blurred vision, intestinal upset), hypoglycemia, torsades de pointes VT; negative inotropic effects (which may worsen heart failure or hypotension)

Drug should be used cautiously in patients with impaired LV function.

Dosage should be decreased in patients with renal insufficiency.

Adverse effects may contribute to nonadherence.

Infusion rate or dosage should be decreased or drug stopped if QRS interval widens (> 50% if initially < 120 millisecond or > 25% if initially > 120 millisecon