Disopyramide

Class Ia

IV DoseNo IV form
Oral dose< 2 yr.: 23-33 mg/kg/day (mean 30)
2-10 yr.: 9-24 mg/kg/day (mean 20)
>10 yr.: 5-13 mg/kg/day (mean 8)
divided q 6 hours, or q 12 hours for CR forms.
Maximum 1200 mg/day.
Levels2-5 ug/ml, poorly correlated with efficacy
KineticsPeak levels at 0.5-3 hours after oral dose. (3.4-4.0 hours after controlled release form). Nonlinear kinetics due to protein binding. Elimination half-life 5-6 hours at therapeutic levels. Large Vd in children.
CautionsCauses significant decreases in contractility! In renal failure, active metabolite (NMD) accumulates, which is even more anticholinergic than parent compound.
InteractionsNone with digoxin.
Atenolol decreases clearance and is synergistic in decreasing cardiac output. (Probably true for allbeta blockers).
Phenytoin increases clearance and decreases levels.
PreparationsNorpace capsules: 100, 150 mg
Norpace CR: controlled release capsules: 100, 150 mg
FDA approval in childrenyes
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