Quinidine

Administration

• Type: Antimalarial, Antiarrhythmic
• Dosage Forms:
• Routes of Administration: IV, oral
• Common Trade Names:

Adult Dosing

Ventricular dysrhythmias

• Quinidine gluconate IV 0.25 mg/kg/min over 20-40 min, max 10 mg/kg per conversion attempt
• PO alternative: 648 mg PO q8 x3-4 doses

Severe malaria

• Load 10 mg/kg IV over 2hrs, then 0.02 mg/kg/min IV/PO x3 days, in conjunction with doxycycline OR
• Load 24 mg/kg IV infused over 4 hours, then 12 mg/kg IV infused over 4h q8h starting 8h after initial loading dose

Pediatric Dosing

• Malaria: same weight-based dosing as above

Special Populations

• Pregnancy Rating: C
• Lactation risk: Infant risk minimal
• Renal dosing: No adjustment
• Hepatic dosing: May lengthen half-life

Indications

• An effective treatment and prevention strategy for:
  • Brugada syndrome arrhythmic electrical storm
  • Idiopathic ventricular fibrillation
  • Early repolarization syndrome (though NOT benign, see benign early repolarization)
  • Congenital short QT syndrome

Contraindications

• Allergy to class/drug
• Cardiac rhythm dependent upon junctional or idioventricular pacemaker (in absence of artificial pacemaker)
• Myasthenia gravis
• History of ITP or TTP associated with quinine or quinidine

Adverse Reactions

Serious

• Prolonged QT, torsades de points, ventricular arrythmia
• Hepatotoxicity
• Kidney disease

Common

• Diarrhea, nausea/vomiting
• Headache, lightheadedness
• Palpitations
• Rash

Pharmacology

• Half-life: 3-8h
• Metabolism: Hepatic
• Excretion:

Mechanism of Action

• Class IA antiarrhythmic: inhibits depolarizing sodium channels in cardiac muscle and purkinje fibers
• Antimalarial action: intraerythrocytic schizonticide to p. vivax and p. malariae, acts against asexual erythrocytic phase of p. falciparum

Comments

• Inexpensive with restricted indications, causing it to be inaccessible in many areas globally
• Main manufacturer halted production in 2010
• Discontinue quinidine infusion if:
  • Sinus rhythym restored
  • QRS complex widens > 130% of pre-treatment QRS duration
  • QTc widens > 130% of pre-treatment duration OR > 500 ms
  • Disappearance of T-waves
  • Development of significant tachycardia, symptomatic bradycardia, hypotension

See Also

• Antimalarial medications
• Antiarrhythmics

References

Authors

Kevin Lu, Claire, Ross Donaldson