علاج Quinidine

GENERIC NAME:Quinidine

BRAND NAMES: Quinaglute, Quinidex

DRUG CLASS AND MECHANISM

Quinidine is used to correct heart rhythm disturbances and is an antiarrhythmic medication. Three actions are responsible for quinidine's ability to stop heart rhythm disturbances (arrhythmias) and prevent their recurrence. Quinidine decreases the speed of electrical conduction in the heart muscle. Quinidine also blocks the normal effect of the vagus nerve on the heart, causing an increase in heart rate. Quinidine reduces the force of contraction of heart muscle cells, and therefore may further impair the pumping efficiency of a failing heart muscle. Quinidine blocks alpha-receptors in peripheral arteries which lowers blood pressure, and can cause excessively low blood pressure when combined with
other blood vessel relaxing drugs vasodilators

PREPARATIONS

Generic quinidine sulfate tablets (200, 300 mg); Quinidex extentabs (300 mg); Quinaglute dura-tabs 324 mg

PRESCRIBED FOR

Quinidine is an antiarrhythmic drug used in the treatment of abnormal heart rhythms, such as
Early (premature) atrial and ventricular beats
Intermittent rapid rhythms (tachycardias) involving the atria and AV junction as well as extra pathways (bypass tracts) between the atria and ventricles
Intermittent atrial fibrillation and flutter
Sinus rhythm after conversion from atrial fibrillation or flutter to prevent recurrence; and
Ventricular tachycardia

DOSING

Quinidine is administered with food. It is metabolized mainly by the liver with a small amount of kidney excretion. Dosages may need to be lowered in patients with liver or kidney dysfunction

DRUG INTERACTIONS

Quinidine should not be taken by people who are known to be allergic to it or quinine. Rarely, quinidine causes a low platelet count by stimulating production of an antiplatelet antibody. Quinidine has also been reported to cause diffuse joint aches as well as liver toxicity (hepatitis). Excess quinidine can induce a syndrome called "cinchonism" consisting of various sound and visual disturbances, rashes, and central nervous system changes including headache, confusion, and loss of consciousness. Quinidine can depress heart muscle function, lower blood pressure, and worsen slow heart beats (bradycardia) as well as aggravate heart block. Quinidine can slow the rate of atrial flutter. Quinidine can cause ventricular tachycardia with loss of consciousness which can develop into ventricular fibrillation, resulting in death. Therefore, patients are usually started on quinidine while being monitored in a hospital setting with constant observation of their heart rhythm

SIDE EFFECTS

The most common side effects are diarrhea and nausea which can occur even at low doses. These symptoms cause discontinuation of the drug in 1/4 to 1/3 of patients. Other side effects include vomiting, heartburn, rash, fever, dizziness, and headache

NURSING MOTHERS

Quinidine can enter breast milk and should be avoided by nursing mothers