Adult Dosing

Conversion of atrial fibrillation/flutter to sinus rhythm

quinidine gluconate

• 648 mg PO q8 hrs x3-4 doses, if desired effect is not achieved then increase PRN until conversion
• Alt: 324 mg PO q8 hrs x2 days, then 648 mg PO q12 hrs x2 days, then 648 mg PO q8 hrs x4 days

quinidine sulfate

• 300-600 mg ER tabs PO q8-12 hr; alt: 400 mg PO qid x4-5 doses; if desired effect is not achieved then increase PRN until conversion

For reducing frequency of relapse into atrial fibrillation/flutter

quinidine gluconate

• Start: 324 mg PO q8-12 hr; adjust dose based on serum levels

quinidine sulfate

• 300-600 mg ER tabs PO q8-12 hr; Alt: 200 mg PO qid; adjust dose based on serum levels

Suppression of life-threatening ventricular arrhythmias

quinidine gluconate

• 648 mg PO q8 hrs x3-4 doses, if desired effect is not achieved then increase PRN until conversion
• Alt: 324 mg PO q8 hrs x2 days, then 648 mg PO q12 hrs x2 days, then 648 mg PO q8 hrs x4 days

quinidine sulfate

• 300-600 mg ER tabs PO q8-12 hr; alt: 400 mg PO qid x4-5 doses; if desired effect is not achieved then increase PRN until conversion

Prevention of supraventricular arrhythmia [Not FDA approved]

quinidine gluconate

• Start: 324 mg PO q8-12 hr; adjust dose based on serum levels

quinidine sulfate

• 300-600 mg ER tabs PO q8-12 hr; alt: 200-300 mg PO q4-6 hr

• Dose of quinidine gluconate ER tABS may be titrated by breaking a tablet in half
• Do not crush/chew the medication
• Adjust dose based on ECG and BP
• Individualize dose

Pediatric Dosing

• Safety and effectiveness in pediatrics have not been established

• As a means of restoring normal sinus rhythm in patients with symptomatic atrial fibrillation/flutter having symptoms not adequately controlled by measures that reduce the rate of ventricular response
• For reducing frequency of relapse into atrial fibrillation/flutter in patients having high risk of symptomatic atrial fibrillation/flutter
• For suppressing recurrent documented ventricular arrhythmias, such as sustained ventricular tachycardia, that in the judgment of the physician are life-threatening

• Hypersensitivity to any of the ingredients of the product
• History of immune thrombocytopenia or thrombocytopenic purpura associated with quinidine or quinine
• Complete atrioventricular block with junctional or idioventricular pacemaker (in the absence of a artificial pacemaker)
• Myasthenia gravis

• Increased mortality has been reported with active antiarrhythmic therapy for non-life-threatening arrhythmias. Patients with structural heart disease are at higher risk
• As per meta-analysis, quinidine when used to prevent or defer recurrence of atrial flutter/fibrillation, the mortality associated with the use of quinidine was more than three times than the mortality associated with the use of placebo and also the mortality associated with the use of quinidine in patients with various non-life-threatening ventricular arrhythmias, was consistently greater than that associated with the use of any of a variety of alternative antiarrhythmics

Renal Dose Adjustment

• Renal impairment: Dose reduction recommended, exact dose adjustments not defined

Hepatic Dose Adjustment

• Hepatic impairment: Dose reduction recommended, exact dose adjustments not defined

See Supplemental Patient Information

• Prolong QT_c interval leading to torsades de pointes, a life-threatening ventricular arrhythmia has been reported with quinidine. Bradycardia, hypokalemia, hypomagnesemia or high serum levels of quinidine increases the risk of torsades. Use cautiously in patients with preexisting long-QT syndromes or history of torsades de pointes
• Ventricular arrhythmias including frequent extrasystoles, ventricular tachycardia, ventricular flutter, and ventricular fibrillation have been reported with quinidine
• Use of quinidine in patients with atrial flutter/fibrillation can lead to slowing of the atrial rate with a consequent increase in the ventricles beats (>200 beats/min). Hence, prior to initiation of quinidine therapy achieve partial atrioventricular block using conduction-reducing drugs such as digitalis, verapamil, diltiazem, or a beta-receptor blocking agent
• Quinidine can cause sinus node depression and bradycardia when used in patients with the sick sinus syndrome
• Physical or pharmacological vagal maneuvers undertaken to terminate paroxysmal supraventricular tachycardia will be ineffective in patients receiving quinidine, as quinidine opposes the atrial and A-V nodal effects of vagal stimulation
• Thrombocytopenia presenting with petechiae or bruising, lightheadedness, chills, fever, nausea, vomiting and bleeding events has been observed with quinidine therapy. Discontinue the therapy on occurence of any of these symptoms and if therapy is continued there is risk of fatal hemorrhage

Cautions: Use cautiously in

• Renal impairment
• Hepatic impairment
• Risk of complete AV block
• preexisting long-QT syndromes
• History of torsades de pointes
• Sick sinus syndrome
• Bradycardia
• Hypokalemia
• Hypomagnesemia
• CHF

Supplemental Patient Information

• Do not take this medication if history of allergic reaction to quinidine or quinine (Qualaquin), including easy bruising or unusual bleeding
• If breast-feeding a baby do not use this medication without consulting a physician
• Stop using the medicine for a short time prior to undergoing any surgery

Pregnancy Category:C

Breastfeeding: Probably safe. Exclusively breastfed infants should be carefully monitored if this drug is used during lactation, possibly including measurement of serum levels to rule out toxicity if there is a concern. This information is based upon LactMed database http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 18 April 2011). According to manufacturer data administration of quinidine should (if possible) be avoided in lactating women who continue to nurse.

• CNS: Dizziness, confusion, fatigue, headache, syncope, vertigo, lightheadedness, insomnia, nervousness
• EENT: Blurred vision, diplopia, mydriasis, photophobia, tinnitus, optic neuritis, altered color perception
• CV: Severe hypotension, QT prolongation, torsades de pointes, ventricular arrhythmias, palpitations, paradoxical ventricular tachycardia, complete AV block, chest pain
• RESP: Respiratory arrest
• GI: Anorexia, abdominal cramping, diarrhea, nausea, vomiting, dyspepsia, drug-induced hepatitis, hepatotoxicity
• DERM: Rash, lupus erythematosus, photosensitivity
• HEMA: Agranulocytosis, hemolytic anemia, thrombocytopenia, thrombocytopenic purpura
• NEURO: Ataxia, tremor
• IMMU: Autoimmune disorders
• MISC: Fever, cinchonism, anaphylactoid reactions, weakness

• Class IA antiarrhythmic; it decreases myocardial excitability and conduction velocity
• Bioavailability 70–80% after oral administration
• Metabolized by the liver; CYP450: 3A4 substrate
• Excreted in urine (5-20% unchanged)
• Half-life: 6-8 hrs (quinidine), 12 hrs (3-hydroxy-quinidine)

US Trade Name(s)

• Only generic available

US Availability

quinidine gluconate (generic)

• ETABS: 324 mg

quinidine sulfate (generic)

• TABS: 200, 300 mg
• ETABS: 300 mg

Canadian Trade Name(s)

• N/A

Canadian Availability

• N/A

UK Trade Name(s)

• N/A

UK Availability

• N/A

Australian Trade Name(s)

• N/A

Australian Availability

• N/A

Cardiovascular

Antiarrhythmic Agents

Group I Antiarrhythmics

• Quinidine Sulfate 200 MG (Quinidine 166 MG) Oral Tablet (Mutual Pharmaceutical Company, Inc.)
• Quinidine Sulfate 200 MG (Quinidine 166 MG) Oral Tablet (Sandoz Inc.)
• Quinidine Sulfate 200 MG (Quinidine 166 MG) Oral Tablet (Watson Laboratories, Inc.)
• Quinidine Sulfate 300 MG (quinidine 249 MG) Extended Release Tablet (TEVA PHARMACEUTICALS USA)
• Quinidine Sulfate 300 MG (quinidine 249 MG) Oral Tablet (Mutual Pharmaceutical Company, Inc.)
• Quinidine Sulfate 300 MG (quinidine 249 MG) Oral Tablet (Sandoz Inc.)
• Quinidine Sulfate 300 MG (quinidine 249 MG) Oral Tablet (Watson Laboratories, Inc.)
• Quinidine gluconate 324 MG Extended Release Tablet (Mutual Pharmaceutical)
• Quinidine gluconate 324 MG Extended Release Tablet (Watson Laboratories, Inc.)