Quinidine

Quinidine is an antiarrhythmic agent for the treatment of abnormal heart rhythms and also malaria.
Crystals or white powder. (NTP, 1992)|Solid
Crystals or white powder. (NTP, 1992)|Quinidine is a cinchona alkaloid consisting of cinchonine with the hydrogen at the 6-position of the quinoline ring substituted by methoxy. It has a role as an alpha-adrenergic antagonist, an antimalarial, an anti-arrhythmia drug, a sodium channel blocker, a muscarinic antagonist, a potassium channel blocker, a P450 inhibitor, an EC 1.14.13.181 (13-deoxydaunorubicin hydroxylase) inhibitor, an EC 3.6.3.44 (xenobiotic-transporting ATPase) inhibitor and a drug allergen. It derives from a hydride of a cinchonan.|An optical isomer of [quinine], extracted from the bark of the Cinchona tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular action potential, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.|Quinidine is an Antiarrhythmic and Cytochrome P450 2D6 Inhibitor. The mechanism of action of quinidine is as a Cytochrome P450 2D6 Inhibitor.|Quinidine is a natural cinchona alkaloid which has potent antiarrhythmic activity and has been used for decades in the treatment of atrial and ventricular arrhythmias. Quinidine has been associated with fever, mild jaundice and clinically apparent liver injury in up to 2% of treated patients.|Quinidine is an alkaloid extracted from the bark of the Cinchona tree with class 1A antiarrhythmic and antimalarial effects. Quinidine stabilizes the neuronal membrane by binding to and inhibiting voltage-gated sodium channels, thereby inhibiting the sodium influx required for the initiation and conduction of impulses resulting in an increase of the threshold for excitation and decreased depolarization during phase 0 of the action potential. In addition, the effective refractory period (ERP), action potential duration (APD), and ERP/APD ratios are increased, resulting in decreased conduction velocity of nerve impulses. Quinidine exerts its antimalarial activity by acting primarily as an intra-erythrocytic schizonticide through association with the heme polymer (hemazoin) in the acidic food vacuole of the parasite thereby preventing further polymerization by heme polymerase enzyme. This results in accumulation of toxic heme and death of the parasite.|An optical isomer of quinine, extracted from the bark of the CHINCHONA tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular ACTION POTENTIALS, and decreases automaticity. Quinidine also blocks muscarinic and alpha-adrenergic neurotransmission.