Usual Adult Dose for Arrhythmias

Tablet (sulfate):100 to 600 mg/dose orally every 4 to 6 hours; begin at 200 mg/dose and titrate to desired effect (maximum daily dose: 3 to 4 g).
Extended Release: 324 to 648 mg (gluconate) orally every 8 to 12 hours or 300 to 600 mg (sulfate) orally every 8 to 12 hours.
IV: 800 mg of quinidine gluconate diluted to 50 mL and given at a rate not to exceed 1 mL/min.

Usual Adult Dose for Malaria

Test Dose: 200 mg quinidine sulfate tablet or quinidine gluconate IM injection to determine possibility of idiosyncratic reaction.

Dosage Regimen 1:
Loading dose: 24 mg/kg of quinidine gluconate diluted in 250 mL infused over 4 hours.
Maintenance dose: Start in 24 hours, 12 mg/kg of quinidine gluconate diluted in 250 mL over 4 hours every 8 hours for 7 days or until oral therapy.

Dosage Regimen 2:
Loading dose: 10 mg/kg of quinidine gluconate diluted in 250 mL over 1 to 2 hours.
Maintenance dose: 0.02 mg/kg/min of quinidine gluconate for up to 72 hours.

Omit quinidine loading dose if patient received more than 40 mg/kg of quinine in preceding 48 hours or mefloquine within preceding 12 hours.

Change to oral quinine once parasite density is less than 1% and patient can receive oral medication to complete treatment course; total duration of treatment (quinidine/quinine): 3 days in Africa or South America; 7 days in Southeast Asia; use in combination with doxycycline, tetracycline, or clindamycin.

Usual Pediatric Dose for Malaria

Test Dose: 200 mg quinidine sulfate tablet or quinidine gluconate IM injection to determine possibility of idiosyncratic reaction.

Dosage Regimen 1:
Loading dose: 24 mg/kg of quinidine gluconate diluted in 250 mL infused over 4 hours.
Maintenance dose: Start in 24 hours, 12 mg/kg of quinidine gluconate diluted in 250 mL over 4 hours every 8 hours for 7 days or until oral therapy.

Dosage Regimen 2:
Loading dose: 10 mg/kg of quinidine gluconate diluted in 250 mL over 1 to 2 hours.
Maintenance dose: 0.02 mg/kg/min of quinidine gluconate for up to 72 hours.

Omit quinidine loading dose if patient received more than 40 mg/kg of quinine in preceding 48 hours or mefloquine within preceding 12 hours.

Change to oral quinine once parasite density is less than 1% and patient can receive oral medication to complete treatment course; total duration of treatment (quinidine/quinine): 3 days in Africa or South America; 7 days in Southeast Asia; use in combination with doxycycline, tetracycline, or clindamycin.

Renal Dose Adjustments

If creatinine clearance is less than 10 mL/minute, administer 75% of normal dose.

Liver Dose Adjustments

Reduce maintenance dose by 50% and monitor serum levels closely.

Precautions

US BOXED WARNING:

• MORTALITY: Active antiarrhythmic therapy has resulted in increased mortality. Risk of active therapy may be greatest in patients with structural heart disease. In a meta-analysis of trials that used this drug to prevent or defer recurrence of atrial flutter/fibrillation, mortality associated with this drug was more than 3 times higher than mortality associated with placebo. In another meta-analysis of trials involving patients with various non-life-threatening ventricular arrhythmias, mortality associated with this drug was consistently greater than mortality associated with any of a variety of alternative antiarrhythmics.

Patients should be monitored on telemetry when first started on quinidine and for 48 hours after steady state. The QTc interval should be checked on a regular basis and with any increase in dose. When using quinidine in patients with atrial flutter/fibrillation, the desired pharmacologic reversion to sinus rhythm may (rarely) be preceded by a slowing of the atrial rate with a consequent increase in the rate of beats conducted to the ventricles. This hazard may be decreased if partial AV block is achieved prior to initiation of quinidine therapy, using conduction reducing drugs such as digitalis, verapamil, diltiazem, or beta-receptor blocking agents.

Dialysis

Quinidine is slightly hemodialyzable (5%-20%). A 200 mg supplemental dose post hemodialysis dose is recommended. Quinidine is not removed by peritoneal dialysis.

Other Comments

Dosages exceeding 648 mg (gluconate) every 8 hours or 600 mg (sulfate) every 6 hours are not recommended except for patients with relatively large actual body weight.