quinidine gluconate

Action and Spectrum

Actions and Spectrum: 

Mechanism of Action: 

quinidine gluconate blocks specific ion channels in cardiac muscle cells, affecting the heart’s electrical conduction. It primarily blocks potassium channels, specifically the rapid component of the delayed rectifier potassium current (IKr) and, to a lesser extent, the inward rectifier potassium current (IK1).

quinidine gluconate prolongs the action potential duration and the effective refractory period of cardiac cells by inhibiting these potassium channels. This can help to normalize abnormal electrical rhythms in the heart and restore normal sinus rhythm. 

quinidine gluconate also exhibits some sodium channel-blocking properties, slowing the rate of depolarization and reducing conduction velocity in cardiac tissue. This additional effect contributes to its antiarrhythmic actions. 

Spectrum of Activity: 

quinidine gluconate has a broad spectrum of activity against various cardiac arrhythmias, including: 

• Supraventricular arrhythmias: quinidine can effectively treat atrial fibrillation, atrial flutter, and paroxysmal supraventricular tachycardia (PSVT). 
• Ventricular arrhythmias: quinidine is also used to treat certain ventricular arrhythmias, including ventricular tachycardia and ventricular premature contractions (PVCs). 

Drug Interaction

Adverse Reaction

Frequency defined 

>10% 

Stomach cramping (22%) 

Anorexia (>10%) 

Diarrhea (>10%) 

Nausea (>10%) 

Diarrhea (35%) 

Lightheadedness (15%) 

Bitter taste (>10%) 

Upper GI distress (>10%) 

Vomiting (>10%)  

1-10% 

Fatigue (7%) 

Rash (5%) 

Sleep disturbance (3%) 

Tremor (2%) 

Blurred vision 

Wheezing 

Angina (6%) 

Weakness (5%) 

Nervousness (2%) 

Incoordination (1%) 

Tinnitus 

Headache (7%)  

Frequency not defined 

Hepatotoxicity 

Diplopia 

Hypotension 

Arthralgia 

Night blindness 

Black Box Warning

Black box warning: 

quinidine gluconate usage is consistently related to higher mortality in individuals with non-life-threatening ventricular arrhythmias than any of the many available antiarrhythmic medications; the risk of death rises with structural heart disease. 

Contraindication / Caution

Contraindications/caution: 

Contraindications: 

• Hypersensitivity: Individuals with known hypersensitivity or allergy to quinidine or other medication components should not use it. 
• Complete Atrioventricular (AV) Block: It is contraindicated in patients with complete heart block (third-degree AV block) unless they have a functioning artificial pacemaker. 
• Long QT Syndrome: It can prolong the QT interval on an electrocardiogram (ECG).  
• Ventricular Tachycardia Associated with Bundle Branch Block: It is contraindicated in patients with ventricular tachycardia associated with bundle branch block unless they have an implanted defibrillator. 
• Recent Myocardial Infarction: quinidine should not be used in patients who have experienced a recent myocardial infarction (heart attack) due to the potential risk of proarrhythmias. 
• Previous Hematologic Toxicity: If a patient has previously experienced hematologic toxicity, such as agranulocytosis or thrombocytopenia while taking quinidine, its use should be avoided. 
• Pre-existing QT Interval Prolongation: It is contraindicated in patients with pre-existing QT interval prolongation, as it may further increase the risk of dangerous arrhythmias. 

Caution: 

• Heart Disease: It should be used cautiously in patients with pre-existing heart disease. 
• Electrolyte Imbalances: It can affect electrolyte levels, particularly potassium, and magnesium. Patients with pre-existing electrolyte imbalances should be closely monitored during quinidine therapy, as these imbalances can increase the risk of arrhythmias. 
• Liver or Kidney Impairment: It is primarily metabolized in the liver, and kidney function can affect its elimination. Therefore, caution is advised when using quinidine in patients with liver or kidney impairment.  
• QT Interval Prolongation: It can prolong the QT interval on an ECG, increasing the risk of dangerous arrhythmias, such as torsades de pointes.  
• Blood Disorders: It can affect blood cell counts, including white blood cells and platelets. Patients with pre-existing blood disorders or medications that affect blood cell counts should be monitored closely when using quinidine. 

Pregnancy / Lactation

Pregnancy consideration: Insufficient data available 

Lactation: Excretion of the drug in human breast milk is known. Caution is necessary. 

Pregnancy category: 

Category A: well-controlled and Satisfactory studies show no risk to the fetus in the first or later trimester. 

Category B: there was no evidence of risk to the fetus in animal studies, and there were not enough studies on pregnant women. 

Category C: there was evidence of risk of adverse effects in animal reproduction studies, and no adequate evidence in human studies must take care of potential risks in pregnant women.    

Category D: adequate data with sufficient evidence of human fetal risk from various platforms, but despite the potential risk, and used only in emergency cases for potential benefits.    

Category X: Drugs listed in this category outweigh the risks over benefits. Hence these categories of drugs need to be avoided by pregnant women.    

Category N: There is no data available for the drug under this category 

Pharmacology

Pharmacology: 

Mechanism of Action:  

quinidine gluconate belongs to the class of Class Ia antiarrhythmic drugs. It blocks various ion channels in the heart, including sodium channels (Class I effect), potassium channels (Class III effect), and calcium channels. By blocking these channels, quinidine slows down the conduction of electrical impulses in the heart, prolongs the action potential duration, and increases the effective refractory period of cardiac cells. 

• Effects on Cardiac Action Potential: quinidine gluconate primarily affects the duration of the cardiac action potential. It slows the rate of depolarization during phase 0 (fast sodium channel blockade), delays repolarization during phase 3 (potassium channel blockade), and can also affect phase 4 (pacemaker potential). These effects result in a lengthening of the QT interval on the electrocardiogram (ECG). 
• Antiarrhythmic Effects: By altering the electrical conduction in the heart, quinidine gluconate helps to normalize and stabilize irregular heart rhythms. It can suppress abnormal electrical activity in the atria and ventricles, thus restoring a normal sinus rhythm. Additionally, quinidine can also suppress ectopic pacemaker activity and reduce the occurrence of premature ventricular contractions. 

Pharmacodynamics: 

quinidine exerts its primary pharmacodynamic effect as an antiarrhythmic medication. Its mechanisms of action involve the blockade of various ion channels in cardiac tissue, stabilizing electrical conduction, and restoring normal cardiac rhythms. 

Pharmacokinetics: 

Absorption 

quinidine sulfate has a bioavailability of approximately 70%, while quinidine gluconate has a 70-80% bioavailability. It reaches peak plasma concentrations around 2 hours after administration, while quinidine gluconate reaches peak plasma concentrations between 3-6 hours. When taken orally, quinidine generally takes effect within 1-3 hours after administration. The duration of action of quinidine is typically around 6-8 hours.  

Distribution 

The volume of distribution of quinidine is approximately 2-3 L/kg in adults and 0.5 L/kg in individuals with heart failure. It is highly protein bound, with approximately 80-88% protein binding in adults and 50-70% in newborns. 

Metabolism 

quinidine is metabolized in the liver primarily through the hepatic P450 enzyme CYP3A4. The significant metabolites of quinidine are 3-hydroxyquinoline and 2-quinidine, some of which retain antiarrhythmic effects. It inhibits the activity of the CYP2D6 enzyme. 

Elimination and Excretion 

The half-life of quinidine is approximately 6-8 hours in adults and 3-4 hours in children. It is cleared from the body with a clearance rate of 3-5 mL/min/kg in adults and 1-2.5 mL/min/kg in children. Approximately 15-25% of quinidine is excreted unchanged in the urine, while around 5% is excreted in feces. It is dialyzable during hemodialysis but is not removed significantly during peritoneal dialysis. 

Adminstartion

Administration: 

Oral administration 

May be consumed with or without meals. 

Patient Information Leaflet

Patient information leaflet 

Generic Name: quinidine gluconate  

Why do we use quinidine gluconate? 

quinidine gluconate is a medication that belongs to the class of antiarrhythmic drugs. It primarily treats irregular heart rhythms, such as atrial fibrillation, atrial flutter, and ventricular arrhythmias. Here are some specific uses of quinidine gluconate: 

• Atrial Fibrillation and Atrial Flutter: quinidine gluconate can be used to restore and maintain normal heart rhythm in patients with atrial fibrillation or atrial flutter, characterized by rapid and irregular contractions of the heart’s upper chambers. 
• Ventricular Arrhythmias: quinidine gluconate can also treat certain ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. These conditions involve abnormal heart rhythms originating from the heart’s lower chambers. 
• Malaria Treatment: quinidine gluconate has been used as an antimalarial drug, particularly for treating severe or complicated malaria cases caused by Plasmodium falciparum.