Quinidine is a medication used to restore normal sinus rhythm, treat atrial fibrillation and flutter, and treat ventricular arrhythmias. Quinidine is a D-isomer of quinine present in the bark of the Cinchona tree and similar plant species.
- Mechanism
- Curator reviewed · 5 references
Quinidine has a complex electrophysiological profile that has not been fully elucidated. The antiarrhythmic actions of this drug are mediated through effects on sodium channels in Purkinje fibers. Quinidine blocks the rapid sodium channel (INa), decreasing the phase zero of rapid depolarization of the action potential. Quinidine also reduces repolarizing K+ currents (IKr, IKs), the inward rectifier potassium current (IK1), and the transient outward potassium current Ito, as well as the L-type calcium current ICa and the late INa inward current. The reduction of these currents leads to the prolongation of the action potential duration. By shortening the plateau but prolonging late depolarization, quinidine facilitates the formation of early afterdepolarisation (EAD). Additionally, in patients with malaria, quinidine acts primarily as an intra-erythrocytic schizonticide, and is gametocidal to Plasmodium vivax and P. malariae, but not to P. falciparum.
- Primary indication
- Quinidine is indicated for the management and prophylactic therapy of atrial fibrillation/flutter, as well as the suppression of recurrent documented ventricular arrhythmias.Curator reviewed · 5 structured indications
- Formula / weight
- C20H24N2O2 · 324.4168 g/mol (avg)
- First approval
- Canada, 2004 · United States, 1950
- Also known as
- (8R,9S)-Quinidine · beta-Quinine · CIN-QUIN · Conchinin · Conquinine
- Brand names
Resolves to
LOUPRKONTZGTKE-LHHVKLHASA-NSMILES[H][C@@]12CCN(C[C@@H]1C=C)[C@]([H])(C2)[C@@H](O)C1=C2C=C(OC)C=CC2=NC=C1What you can answer from here — as of September 28, 2026
Which drugs share a target with Quinidine, and which of those have an active Phase 3 trial?
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