Quinidine-pharmaceutical agent that acts as a class I antiarrhythmic agent in the heart.

Quinidine is a pharmaceutical agent that acts as a class I antiarrhythmic agent (Ia) in the heart. It is a stereoisomer of quinine, originally derived from the bark of the cinchona tree. The drug causes increased action potential duration, as well as a prolonged QT interval.

Quinidine-pharmaceutical agent that acts as a class I antiarrhythmic agent in the heart.

Quinidine; (+)-Quinidine; Chinidin; Pitayine; Cin-Quin

Natcardine, Quinidine

(S)-[(2R,4S,5R)-5-ethenyl-1-azabicyclo[2.2.2]octan-2-yl](6-methoxyquinolin-4-yl)methanol

It is a hydantoin anticonvulsant, used with phenobarbital or alone or with other anticonvulsants to manage tonic-clonic seizures, psychomotor seizures, neuropathic pain syndromes including diabetic neuropathy, digitalis-induced cardiac arrhythmias, and cardiac arrhythmias associated with QT-interval prolongation. Quinidine acts on sodium channels on the neuronal cell membrane, limiting the spread of seizure activity and reducing seizure propagation. Quinidine may also act on the slow inward calcium current (ICa), the rapid (IKr) and slow (IKs) components of the delayed potassium rectifier current, the inward potassium rectifier current (IKI), the ATP-sensitive potassium channel (IKATP) and Ito.

• 200-300 mg/day 3-4 times as PO for arrhythmia
• 300-600 mg/day 3-4 times for malaria as sulfate

For the treatment of ventricular pre-excitation and cardiac dysrhythmias

Muscle weakness, nausea, vomiting, diarrhoea; cinchonism symptoms including impaired hearing, headache, blurred vision, dizziness and vomiting; urticaria and skin reactions. Asystole, syncope, ventricular fibrillation. Thrombocytopenia, exfoliative dermatitis, granulomatous hepatitis (hypersensitivity); CHF; heart block, ventricular arrhythmias, tachycardia, seizure, coma.

• Increases plasma digitalis concentration.
• May enhance effects of antihypertensives, vasodilators, myocardiac depressants, oral anticoagulants and non-depolarizing muscle relaxants.
•  Reduced clearance when used with drugs that alkalinise the urine eg. thiazides.
• Plasma levels increased when used with amiodarone or cimetidine.
• Increased metabolism when used with enzyme inducers eg. phenobarbital, phenytoin and rifampicin.
• Decreased metabolism when used with verapamil.
• Increased serum levels of procainamide and haloperidol.

Hypersensitivity, complete heart block, history of thrombocytopenia during treatment with quinine or quinidine, digitalis intoxication.

Store at 20-25°C. 

Molecular weight

324.4168

Molecular formula

C20H24N2O2

CAS number

56-54-2

Precautions

• Test dose is recommended. widening QRS complex; Atrial flutter; incomplete AV block; myasthenia gravis, uncompensated heart failure, acute infections, fever, digitalised patients; hypokalaemia; acute MI; obstructive GI tract changes; renal or hepatic impairment; elderly.
• Prolonged QT interval, history of torsade de pointes, myocarditis, severe myocardial damage.
• Hypotension and vascular collapse may result when rapid infusion.
•  Pregnancy and lactation.