Quinidine bisulfate
Quinidine bisulfate (Biquin Durules)
Quinidine
( KWIN-ih-deen)
Pregnancy Category: D Biquin Durules (Rx)
Quinidine gluconate
Quinidine gluconate (Dura-Tabs)
Quinidine
( KWIN-ih-deen)
Pregnancy Category: C Quinaglute Dura-Tabs Quinalan Quinate (Rx)
Quinidine polygalacturonate
Quinidine polygalacturonate (Cardioquin)
Quinidine
( KWIN-ih-deen)
Pregnancy Category: C Cardioquin (Rx)
Quinidine sulfate
Quinidine sulfate (Quinora)
Quinidine
( KWIN-ih-deen)
Pregnancy Category: C Apo-Quinidine Quinidex Extentabs Quinora (Rx)

Classification: Antiarrhythmic, class IA

See Also: See also Antiarrhythmic Agents .

Action/Kinetics: Reduces the excitability of the heart and depresses conduction velocity and contractility. Prolongs the refractory period and increases conduction time. It also decreases CO and possesses anticholinergic, antimalarial, antipyretic, and oxytocic properties. PO: Onset: 0.5-3 hr. Maximum effects, after IM: 30-90 min. t 1/2: 6-7 hr. Time to peak levels, PO: 3-5 hr for gluconate salt, 1-1.5 hr for sulfate salt, and 6 hr for polygalacturonate salt; IM: 1 hr. Therapeutic serum levels: 2-6 mcg/mL. Protein binding: 60%-80%. Duration: 6-8 hr for tablets/capsules and 12 hr for extended-release tablets. Metabolized by liver. Urine pH affects rate of urinary excretion (10%-50% excreted unchanged).

Uses: Premature atrial, AV junctional, and ventricular contractions. Treatment and control of atrial flutter, established atrial fibrillation, paroxysmal atrial tachycardia, paroxysmal AV junctional rhythm, paroxysmal and chronic atrial fibrillation, paroxysmal ventricular tachycardia not associated with complete heart block, maintenance therapy after electrical conversion of atrial flutter or fibrillation. The parenteral route is indicated when PO therapy is not feasible or immediate effects are required. Investigational: Gluconate salt for life-threatening Plasmodium falciparum malaria.

Contraindications: Hypersensitivity to drug or other cinchona drugs. Myasthenia gravis, history of thrombocytopenic purpura associated with quinidine use, digitalis intoxication evidenced by arrhythmias or AV conduction disorders. Also, complete heart block, left bundle branch block, or other intraventricular conduction defects manifested by marked QRS widening or bizarre complexes. Complete AV block with an AV nodal or idioventricular pacemaker, aberrant ectopic impulses and abnormal rhythms due to escape mechanisms. History of drug-induced torsades de pointes or long QT syndrome.

Special Concerns: Safety in children and during lactation has not been established. Use with extreme caution in clients in whom a sudden change in BP might be detrimental or in those suffering from extensive myocardial damage, subacute endocarditis, bradycardia, coronary occlusion, disturbances in impulse conduction, chronic valvular disease, considerable cardiac enlargement, frank CHF, and renal or hepatic disease. Use with caution in acute infections, hyperthyroidism, muscular weakness, respiratory distress, and bronchial asthma. The dose in geriatric clients may have to be reduced due to age-related changes in renal function.

Side Effects: CV: Widening of QRS complex, hypotension, cardiac asystole ectopic ventricular beats, ventricular tachycardia or fibrillation, torsades de pointes paradoxical tachycardia, arterial embolism ventricular extrasystoles (one or more every 6 beats), prolonged QT interval, complete AV block, ventricular flutter. GI: N&V;, abdominal pain, anorexia, diarrhea, urge to defecate as well as urinate, esophagitis (rare). CNS: Syncope, headache, confusion, excitement, vertigo, apprehension, delirium, dementia, ataxia, depression. Dermatologic: Rash, urticaria, exfoliative dermatitis, photosensitivity, flushing with intense pruritus, eczema, psoriasis, pigmentation abnormalities. Allergic: Acute asthma, angioneurotic edema, respiratory arrest dyspnea, fever, vascular collapse purpura, vasculitis, hepatic dysfunction (including granulomatous hepatitis), hepatic toxicity. Hematologic: Hypoprothrombinemia, acute hemolytic anemia thrombocytopenic purpura, agranulocytosis thrombocytopenia, leukocytosis, neutropenia, shift to left in WBC differential. Ophthalmologic: Blurred vision, mydriasis, alterations in color perception, decreased field of vision, double vision, photophobia, optic neuritis, night blindness, scotomata. Other: Liver toxicity including hepatitis, lupus nephritis, tinnitus, decreased hearing acuity, arthritis, myalgia, increase in serum skeletal muscle CPK, lupus erythematosus.

Laboratory Test Alterations: False + or PSP, 17-ketosteroids, PT.

Overdose Management: Symptoms: CNS: Lethargy, confusion, coma, seizures, respiratory depression or arrest headache, paresthesia, vertigo. CNS symptoms may be seen after onset of CV toxicity. GI: Vomiting, diarrhea, abdominal pain, hypokalemia, nausea. CV: Sinus tachycardia, ventricular tachycardia or fibrillation, torsades de pointes, depressed automaticity and conduction (including bundle branch block, sinus bradycardia, SA block, prolongation of QRS and QTc, sinus arrest, AV block, ST depression, T inversion), syncope, heart failure. Hypotension due to decreased conduction and CO and vasodilation. Miscellaneous: Cinchonism, visual and auditory disturbances, hypokalemia, tinnitus, acidosis. Treatment: Perform gastric lavage, induce vomiting, and administer activated charcoal if ingestion is recent. Monitor ECG, blood gases, serum electrolytes, and BP. Institute cardiac pacing, if necessary. Acidify the urine. Use artificial respiration and other supportive measures. Infusions of 1/6 molar sodium lactate IV may decrease the cardiotoxic effects. Treat hypotension with metaraminol or norepinephrine after fluid volume replacement. Use phenytoin or lidocaine to treat tachydysrhythmias. Hemodialysis is effective but not often required.

Drug Interactions: Acetazolamide, Antacids / Quinidine effect R/T renal excretion Amiodarone / Quinidine levels with possible fatal cardiac dysrhythmias Anticholinergic agents, Atropine / Additive effect on blockade of vagus nerve action Anticoagulants, oral / Additive hypoprothrombinemia with possible hemorrhage Barbiturates / Quinidine effect R/T liver breakdown Belladonna leaf/root / Increased anticholinergic effect Cholinergic agents / Quinidine antagonizes effect of cholinergic drugs Cimetidine / Quinidine effect R/T liver breakdown Digoxin / Symptoms of digoxin or digitoxin toxicity Disopyramide / Either disopyramide levels or quinidine levels Guanethidine / Additive hypotensive effect Henbane leaf / Anticholinergic effects Lily-of-the-valley / Effect and side effects of quinidine Methyldopa / Additive hypotensive effect Metoprolol / Metoprolol effect in fast metabolizers Neuromuscular blocking agents / Respiratory depression Nifedipine / Quinidine effect Pheasant's eye herb / Effect and side effects of quinidine Phenobarbital, Phenytoin / Quinidine effect R/T rate of liver metabolism Potassium / Quinidine effect Procainamide / Procainamide effects with possible toxicity Propafenone / Serum propafenone levels in rapid metabolizers Propranolol / Propranolol effect in fast metabolizers Rifampin / Quinidine effect R/T liver breakdown Scopolia root / Quinidine effect Skeletal muscle relaxants / Skeletal muscle relaxation Sodium bicarbonate / Quinidine effect R/T renal excretion Squill / Effect and side effects of quinidine Sucralfate / Serum quinidine levels effect Thiazide diuretics / Quinidine effect R/T renal excretion Tricyclic antidepressants / TCA effect R/T clearance Verapamil / Verapamil clearance hypotension, bradycardia, AV block, VT, and pulmonary edema

How Supplied: Quinidine bisulfate: Sustained-release tablet: 250 mg. Quinidine gluconate: Injection: 80 mg/mL; Tablet, extended release: 324 mg. Quinidine polygalacturonate: Tablet: 275 mg. Quinidine sulfate: Tablet: 200 mg, 300 mg; Tablet, extended release: 300 mg

Dosage
?Quinidine Bisulfate Sustained-Release Tablets Antiarrhythmic.
Initial: Test dose of 200 mg in the morning (to ascertain hypersensitivity). In the evening, administer 500 mg. Then, beginning the next day, 500-750 mg/12 hr. Maintenance: 0.5-1.25 g morning and evening.
?Quinidine Polygalacturonate Tablets, Quinidine Sulfate Tablets Premature atrial and ventricular contractions.
Adults: 200-300 mg t.i.d.-q.i.d.
Paroxysmal SVTs.
Adults: 400-600 mg q 2-3 hr until the paroxysm is terminated.
Conversion of atrial flutter.
Adults: 200 mg q 2-3 hr for five to eight doses; daily doses can be increased until rhythm is restored or toxic effects occur.
Conversion of atrial flutter, maintenance therapy.
Adults: 200-300 mg t.i.d.-q.i.d. Large doses or more frequent administration may be required in some clients.
?Quinidine Gluconate Extended-Release Tablets, Quinidine Sulfate Extended-Release Tablets All uses.
Adults: 300-600 mg q 8-12 hr.
?Quinidine Gluconate Injection (IM or IV) Acute tachycardia.
Adults, initial: 600 mg IM; then, 400 mg IM repeated as often as q 2 hr.
Arrhythmias.
Adults: 330 mg IM or less IV (as much as 500-750 mg may be required).
P. falciparum malaria.
Two regimens may be used. (1) Loading dose: 15 mg/kg in 250 mL NSS given over 4 hr; then, 24 hr after beginning the loading dose, institute 7.5 mg/kg infused over 4 hr and given q 8 hr for 7 days or until PO therapy can be started. (2) Loading dose: 10 mg/kg in 250 mL NSS infused over 1-2 hr followed immediately by 0.02 mg/kg/min for up to 72 hr or until parasitemia decreases to less than 1% or PO therapy can be started.