Quinacard SR Uses, Dosage, Side Effects and more
An optical isomer of quinine, extracted from the bark of the Cinchona tree and similar plant species. This alkaloid dampens the excitability of cardiac and skeletal muscles by blocking sodium and potassium currents across cellular membranes. It prolongs cellular action potential, and decreases automaticity. Quinacard SR also blocks muscarinic and alpha-adrenergic neurotransmission.
Quinacard SR, a hydantoin anticonvulsant, is used alone or with phenobarbital or 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.
| Trade Name | Quinacard SR |
| Availability | Prescription only |
| Generic | Quinidine |
| Quinidine Other Names | (8R,9S)-Quinidine, beta-Quinine, Chinidin, Chinidinum, CIN-QUIN, Conchinin, Conquinine, Pitayine, Quinidina |
| Related Drugs | propranolol, doxycycline, clindamycin, amiodarone, lidocaine, hydroxychloroquine, verapamil, Plaquenil, Inderal, Cleocin |
| Type | |
| Formula | C20H24N2O2 |
| Weight | Average: 324.4168 Monoisotopic: 324.183778022 |
| Protein binding | 80-88% |
| Groups | Approved, Investigational |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | Egypt |
| Last Updated: | January 7, 2025 at 1:49 am |
Uses
Quinacard SR 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
Quinacard SR 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 Quinacard SR works
Quinacard SR 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. Quinacard SR 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.
Quinacard SR Drug Interaction
Major: ciprofloxacin, digoxin, escitalopram, ondansetron, sertralineModerate: donepezil, celecoxib, warfarin, phenytoin, apixaban, metoprololUnknown: spironolactone, zolpidem, furosemide, enoxaparin, esomeprazole, clopidogrel, ketorolac, cholecalciferol, simvastatin
Quinacard SR 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.
