Overview
DESCRIPTION Quinidine is an antimalarial schizonticide and an antiarrhythmic agent with Class Ia activity; it is the d-isomer of quinine, and its molecular weight is 324.43. Quinidine gluconate is the gluconate salt of quinidine; its chemical name is cinchonan-9-ol, 6'-methoxy-, (9S)-, mono-D-gluconate; its structural formula is: Its empirical formula is C 20 H 24 N 2 O 2 • C 6 H 12 O 7 , and its...
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacokinetics and Metabolism The absolute bioavailability of quinidine from quinidine gluconate is 70 to 80%. Relative to a solution of quinidine sulfate, the bioavailability of quinidine from quinidine gluconate is reported to be 1.03. The less-than-complete bioavailability is thought to be due to first-pass elimination by the liver. Peak serum levels generally appear 3 to 5 hours after dosing; when the drug is taken with food, absorption is increased in both rate (27%) and extent (17%). The rate and extent of absorption of quinidine from quinidine gluconate are not significantly affected by the coadministration of an aluminum-hydroxide antacid. The rate of absorption of quinidine following the ingestion of grapefruit juice may be decreased.
Indications
- INDICATIONS & 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 gluconate is indicated as a means of restoring normal sinus rhythm. If this use of quinidine gluconate does not restore sinus rhythm within a reasonable time (see DOSAGE AND ADMINISTRATION ), then quinidine gluconate should be discontinued.
Common Doses
- 648 mg
- 403 mg
- 324 mg
- 202 mg
Dosage
DOSAGE & ADMINISTRATION The dose of quinidine delivered by quinidine gluconate extended-release tablets may be titrated by breaking a tablet in half. If tablets are crushed or chewed, their extended-release properties will be lost. The dosage of quinidine varies considerably depending upon the general condition and the cardiovascular state of the patient. Conversion of atrial fibrillation/flutter to sinus rhythm Especially in patients with known structural heart disease or other risk factors for toxicity, initiation or dose-adjustment of treatment with quinidine gluconate should generally be...
Contraindications
- CONTRAINDICATIONS Quinidine is contraindicated in patients who are known to be allergic to it, or who have a history of immune thrombocytopenia or have developed thrombocytopenic purpura during prior therapy with quinidine or quinine (see WARNINGS ). In the absence of a functioning artificial pacemaker, quinidine is also contraindicated in any patient whose cardiac rhythm is dependent upon a junctional or idioventricular pacemaker, including patients in complete atrioventricular block.
Side Effects
- 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 the reported study that was closest in character to the predominant approved use of quinidine gluconate, 86 adult outpatients with atrial fibrillation were followed for six months while they received slow-release quinidine bisulfate tablets, 600 mg (approximately 400 mg of...
Interactions
- No major interactions listed on the FDA label. Always consult a healthcare professional.