Quinidine
Mechanism :
Quinidine, a salt of quinine is derived from an alkaloid obtained from the plant, cinchona. It is used to treat cardiac arrhythmias like supraventricular tachycardias, atrial fibrillation & flutter and premature heartbeats. It is generally not used in children.
Indication :
- Cardiac arrhythmias (paroxysmal supraventricular tachycardia, ventricular tachycardia pre-dysrhythmias)
- Treatment of severe malaria
Contraindications :
Hypersensitivity.
Thrombocytopenic purpura hx, quinidine or quinine-assoc.
Myasthenia gravis, Intraventricular conduction defects, Complete AV block w/ junctional rhythm, Complete AV block w/ idioventricular rhythm, ongenital long QT syndrome, uncorrected Electrolyte abnormalities.
Dosing :
Cardiac arrhythmias:
Oral (Quinidine Sulfate):
Test dose 2 mg/kg PO. Then 10 to 30 mg/kg/day PO or 900 mg/m²/day PO, given in divided doses every 6 hours.
IV (Quinidine Gluconate):
2-10 mg/kg IV every 3-6 hours. It is contraindicated in complete AV blocks, Digitalis induced AV conduction defects.
Treatment of severe malaria:
IV (Quinidine Gluconate):
10 mg/kg/dose (6.25 mg/kg/dose base) IV loading dose over 1 to 2 hours, then a continuous maintenance infusion of 0.02 mg/kg/minute (0.0125 mg/kg/minute base) IV for at least 24 hours. Give in combination with
doxycycline,
tetracycline, or
clindamycin. Continue treatment for 7 days. In patients, able to swallow shift to oral
quinine sulfate.
Adverse Effect :
Syncope, GI disturbances, light headedness, hypotension, tachycardia, arrhythmias, blood dyscrasias, hepatotoxicity and cardiac arrest.
Interaction :
Interaction Characteristics:
CYP3A4 substrate; P-gp (MDR1) substrate; CYP2D6 inhibitor, strong; P-gp (MDR1) inhibitor, strong; GI absorption enhanced by GLP-2 receptor agonist; bradycardia; prolongs QT interval, definite; urine pH sensitive.
Contraindicated:
Amitriptyline, Amoxapine, Atazanavir, Cisapride, Clomipramine, Darunavir, Desipramine, Doxepin, Dronedarone, Fingolimod, Fosamprenavir, Gemifloxacin, Imipramine, Indinavir, Levofloxacin, Lopinavir/Ritonavir, Mifepristone, Moxifloxacin, Nelfinavir, Norfloxacin, Nortriptyline, Ofloxacin, Pimozide, Posaconazole, Protriptyline, Quinidine (CYP2D6 Booster), Ritonavir, Saquinavir, Tacrolimus, Thioridazine, Tipranavir, Toremifene, Trimipramine, Voriconazole, Ziprasidone.
Avoid/Use Alternative:
Amiloride, Amiodarone, Arsenic Trioxide, Artemether/Lumefantrine, Asenapine, Atracurium, Azithromycin, Bedaquiline, Betaxolol Ophthalmic, Boceprevir, Carteolol Ophthalmic, Chloramphenicol, Cimetidine, Ciprofloxacin, Cisatracurium, Citalopram, Clarithromycin, Clozapine, Cobicistat, Codeine, Conivaptan, Crizotinib, Cyclosporine, Dabigatran Etexilate, Dabrafenib, Danazol, Dasatinib, Degarelix, Delavirdine, Diltiazem, Disopyramide, Dofetilide, Ephedra, Ephedrine, Eribulin, Erythromycin, Escitalopram, Flecainide, Fluconazole, Goserelin, Granisetron, Haloperidol, Histrelin, Hydrocodone, Ibutilide, Iloperidone, Imatinib, Itraconazole, Ketoconazole, Lapatinib, Leuprolide, Levobunolol Ophthalmic, Methadone, Metipranolol Ophthalmic, Nefazodone, Nilotinib, Ondansetron, Paliperidone, Pancuronium, Pasireotide, Pazopanib, Pentamidine, Procainamide, Propafenone, Quetiapine, Quinidine (Antiarrhythmic), Quinine, Ranolazine, Rocuronium, Romidepsin, Sirolimus, Sodium Phosphate (Bowel Prep), Sodium Phosphate Rectal, Sorafenib, Sotalol, Succinylcholine, Sunitinib, Telaprevir, Telavancin, Telithromycin, Tetrabenazine, Timolol Ophthalmic, Trazodone, Triptorelin, Vandetanib, Vardenafil, Vecuronium, Vemurafenib, Venlafaxine, Verapamil.
Hepatic Dose :
Dose reduction will be required due to reduced clearance of quinidine. Adjust dose based on clinical response.