Quinidine sulfate

Quinidine Sulfate is a pharmaceutical drug used primarily to treat cardiac arrhythmias. It is a stereoisomer of quinine, which is an anti-malarial drug. Quinidine Sulfate is classified as a Class Ia antiarrhythmic agent, and it works by blocking the fast inward sodium current, thereby prolonging the action potential duration.

History

Quinidine Sulfate was first isolated from the bark of the cinchona tree in the early 19th century. It was initially used as an anti-malarial drug, but its cardiac effects were soon recognized, and it was repurposed as an antiarrhythmic agent.

Pharmacology

Quinidine Sulfate blocks the fast inward sodium current, which results in a decrease in the phase 0 depolarization. This prolongs the action potential duration and refractory period, which can help to stabilize the cardiac rhythm.

Clinical Use

Quinidine Sulfate is used to treat a variety of cardiac arrhythmias, including atrial fibrillation, atrial flutter, and ventricular tachycardia. It is also used in the treatment of malaria, although this use is less common due to the development of more effective anti-malarial drugs.

Side Effects

Common side effects of Quinidine Sulfate include nausea, diarrhea, and dizziness. More serious side effects can include cardiotoxicity, thrombocytopenia, and hepatotoxicity.

Contraindications

Quinidine Sulfate is contraindicated in patients with a history of torsades de pointes, a type of ventricular tachycardia, and in patients with known hypersensitivity to the drug.

See Also

• Antiarrhythmic agent
• Cardiac arrhythmia
• Quinine
• Cinchona tree