Quinidine Sulfate Tablet

INDICATIONS AND USAGE Conversion of Atrial Fibrillation/Flutter In patients with symptomatic atrial fibrillation/flutter whose symptoms are not adequately controlled by measures that reduce the rate of ventricular response, quinidine sulfate is indicated as a means of restoring normal sinus rhythm. If this use of quinidine sulfate does not restore sinus rhythm within a reasonable time (see DOSAGE AND ADMINISTRATION ), then quinidine sulfate should be discontinued.

ADVERSE REACTIONS Quinidine preparations have been used for many years, but there are only sparse data from which to estimate the incidence of various adverse reactions. The adverse reactions most frequently reported have consistently been gastrointestinal, including diarrhea, nausea, vomiting, and heartburn/esophagitis. In one study of 245 adult outpatients who received quinidine to suppress premature ventricular contractions, the incidences of reported adverse experiences were as shown in the table below. The most serious quinidine-associated adverse reactions are described above under WARNINGS .

Pregnancy Pregnancy Category C Animal reproductive studies have not been conducted with quinidine. There are no adequate and well-controlled studies in pregnant women. Quinidine should be given to a pregnant woman only if clearly needed. Human placental transport of quinidine has not been systematically studied. In one neonate whose mother had received quinidine throughout her pregnancy, the serum level of quinidine was equal to that of the mother, with no apparent ill effect. The level of quinidine in amniotic fluid was about three times higher than that found in serum.

WARNINGS Mortality In many trials of antiarrhythmic therapy for non-life-threatening arrhythmias, active antiarrhythmic therapy has resulted in increased mortality; the risk of active therapy is probably greatest in patients with structural heart disease. In the case of quinidine used to prevent or defer recurrence of atrial flutter/fibrillation, the best available data come from a metaanalysis CLINICAL PHARMACOLOGY/Clinical Effects above. In the patients studied in the trials there analyzed, the mortality associated with the use of quinidine was more than three times as great as the mortality associated with the use of placebo. CONTRAINDICATIONS Quinidine is contraindicated in patients who are known to be allergic to it, or who have developed thrombocytopenic purpura during prior therapy with quinidine or quinine.