Class 1a

IV DoseDon’t! Frequent occurrence of hypotension and cardiovascular collapse!
Oral doseQuinidine sulfate: 30-60 mg/kg/day (450-900 mg/m2/day) in children, 10 mg/kg/day in adults, divided q 6 hours.
20% higher for gluconate, given q 8-12 hours
Levels2-6 ug/ml >7 ug/ml highly correlated with toxicity.
KineticsPeak levels 1-3 hours for sulfate, 4 hours for gluconate after oral dose. Elimination half-life 6.3 hours in adults. 4.7 hours in 4-6 year olds, 6 hours in neonates.
CautionsSimilar to those for procainamide
InteractionsPotentiation of warfarin effect. Mean 100-150% increase in digoxin levels. (Probably doesn’t occur under 2 months of age.) Levels increased in congestive heart failure. Elimination impaired by cimetidine, amiodarone. Elimination accelerated by phenytoin, propranolol, rifampin. Contraindicated with verapamil: cardiovascular collapse and hypotension frequent.
PreparationsQuinidine sulfate tablets: 200, 300 mg.
Quinidex Extentabs (Q. sulfate): 1/3 released immediately, 2/3 slow release in GI tract. 300 mg tablets.
Quiniglute Duratabs: non-scored tablets: 324 mg
FDA approval in childrenno