Chinidinum

Uses

Chinidinum is a medication used to restore normal sinus rhythm, treat atrial fibrillation and flutter, and treat ventricular arrhythmias.

For the treatment of ventricular pre-excitation and cardiac dysrhythmias

Chinidinum is also used to associated treatment for these conditions: Atrial Fibrillation or Flutter, Malaria caused by Plasmodium falciparum, Pseudobulbar affect, Arrhythmia of ventricular origin

How Chinidinum works

Chinidinum acts on sodium channels on the neuronal cell membrane, limiting the spread of seizure activity and reducing seizure propagation. The antiarrhythmic actions are mediated through effects on sodium channels in Purkinje fibers. Chinidinum 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.

Food Interaction

• Exercise caution with grapefruit products. Grapefruit may delay the absorption of quinidine, and inhibit its metabolism through CYP3A4.
• Exercise caution with St. John's Wort.
• Take separate from antacids. Antacids may reduce the absorption of quinidine.
• Take with or without food. Taking quinidine with food may slow its absorption.

[Moderate] GENERALLY AVOID: In a small, randomized, crossover study, the administration of quinidine with grapefruit juice (compared to water) to healthy volunteers significantly prolonged the time to reach peak plasma quinidine concentrations and decreased the plasma concentrations of its major metabolite, 3-hydroxyquinidine.

These changes were associated pharmacodynamically with both a delay and a reduction in the maximal effect on QTc interval.

The proposed mechanism is delay of gastric emptying as well as inhibition of CYP450 3A4-mediated first-pass metabolism in the gut wall induced by certain compounds present in grapefruits.

MANAGEMENT: Given the drug's narrow therapeutic index, patients receiving quinidine therapy should avoid the consumption of grapefruits and grapefruit juice to prevent any undue fluctuations in plasma drug levels.

Chinidinum Drug Interaction

Major: ciprofloxacin, digoxin, escitalopram, ondansetron, sertralineModerate: donepezil, celecoxib, warfarin, phenytoin, apixaban, metoprololUnknown: spironolactone, zolpidem, furosemide, enoxaparin, esomeprazole, clopidogrel, ketorolac, cholecalciferol, simvastatin

Chinidinum Disease Interaction

Major: cardiovascular dysfunction, proarrhythmic effects, anticholinergic activity, sinus-AV node dysfunctionModerate: electrolyte imbalance, liver dysfunction, renal dysfunction

Volume of Distribution

• 2 to 3 L/kg
• 0.5 L/kg [congestive heart failure]
• 3 to 5 L/kg [cirrhosis of the liver]

Half Life

6-8 hours

Clearance

• 3 – 5 mL/min/kg [adults]

Elimination Route

When the urine pH is less than 7, about 20% of administered quinidine appears unchanged in the urine, but this fraction drops to as little as 5% when the urine is more alkaline.

Innovators Monograph

You find simplified version here Chinidinum