Quinidine is a class IA antiarrhythmic agent used to treat heart rhythm disturbances. It is a stereoisomer of antimalarial agent quinine, originally derived from the bark of the cinchona tree. The drug causes increased action potential duration, as well as a prolonged QT interval. As of 2019 its IV formulation is no longer being manufactured for use in the United States. Medical uses
Quinidine is occasionally used as a class I antiarrhythmic agent to prevent ventricular arrhythmias, particularly in Brugada Syndrome, although its safety in this indication is uncertain.It reduces the recurrence of atrial fibrillation after patients undergo cardioversion, but it has proarrhythmic effects and trials suggest that it may lead to an overall increased mortality in these patients.Quinidine is also used to treat short QT syndrome.Eli Lilly has discontinued manufacture of parenteral quinidine gluconate in the US, and its future availability in many countries is uncertain. Other uses
There is one study supporting the use of a novel combination of dextromethorphan and low dose quinidine in alleviating symptoms of easy laughing and crying (pseudobulbar affect); these are a type rather severe uncontrollable behaviors which can be present in various neurological pathologies such as amyotrophic lateral sclerosis and multiple sclerosis. The dose of quinidine (10mg two times daily) is about 1/40th of a relatively low antiarrhythmic dose (400mg, twice or 3 times daily, as an example; antiarrhythmic doses can sometimes exceed 1500mg/day).
The man had found by chance that when he took one gram of quinine during an attack, it reliably halted it in 25 minutes; otherwise it would last for two to 14 days. Wenckebach often tried quinine again, but he succeeded in only one other patient.He made passing mention of it in his book on cardiac arrhythmias published in 1914. Four years later, Walter von Frey of Berlin reported in a leading Viennese medical journal that quinidine was the most effective of the four principal cinchona alkaloids in controlling atrial arrhythmias. Chemistry
Quinidine-based ligands are used in AD-mix-β for sharpless asymmetric dihydroxylation. Veterinary use
Quinidine sulfate is used in the treatment of atrial fibrillation in horses. References
External links
MedlinePlus
Poisons Information Monograph