quinidine

Quinidine is a prescription small molecule drug classified as a class Ia antiarrhythmic and antimalarial agent. It is primarily used to treat and prevent certain types of abnormal heart rhythms, including atrial fibrillation, atrial flutter, and life-threatening ventricular arrhythmias. Mechanistically, it works by blocking voltage-gated sodium channels in cardiac tissue (sodium channel protein type 5 subunit alpha), thereby slowing electrical conduction and prolonging the action potential duration in the heart. This helps restore normal sinus rhythm but also prolongs the QT interval, which can increase the risk of torsades de pointes and other arrhythmias. Additionally, quinidine has anticholinergic effects, negative inotropic activity (reducing cardiac contractility), and acts as an α-adrenergic antagonist (vasodilator). Quinidine is also used as an antimalarial agent against Plasmodium falciparum by interfering with parasite metabolism within red blood cells. It has been studied at low doses in combination with dextromethorphan for pseudobulbar affect but this use is not standard[1][2][3][4][5][6].

Brand names

Quin-GCardioquinQuinoraQuinidex ExtentabsQuinaglute Dura-TabsQuin-Release

Other names

quinidine sulfatequinidine gluconate