quinidine

Absorption: Bioavailability of oral formulations is 70–80%. Extended-release preparations are absorbed slowly following oral administration.

Distribution: Widely distributed. Cross the placenta; enter breast milk.

Metabolism/Excretion: Metabolized by the liver; 5–20% excreted unchanged by the kidneys.

Half-life: 6–8 hr (↑ in HF or severe liver impairment).

Time/Action Profile ⬆ ⬇

(antiarrhythmic effects)

ROUTE	ONSET	PEAK	DURATION
PO (sulfate)	30 min	1–1.5 hr	6–8 hr
PO (sulfate-ER)	unknown	4 hr	8–12 hr
PO (gluconate)	unknown	3–4 hr	6–8 hr

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity
Conduction defects (in the absence of a pacemaker)
Myasthenia gravis.

Use Cautiously in:

HF (dose reduction recommended)
Severe liver disease (dose ↓ recommended)
Hypokalemia or hypomagnesemia (↑ risk of torsades de pointes)
Bradycardia (↑ risk of torsades de pointes)
Renal impairment
OB: Lactation: Pedi: Safety not established; extended-release preparations should not be used in children.

Adv. Reactions/Side Effects ⬆ ⬇

CV: arrhythmias, HYPOTENSION, palpitations, tachycardia, TORSADES DE POINTES.

Derm: rash.

EENT: blurred vision, diplopia, mydriasis, photophobia, tinnitus.

GI: abdominal cramping, anorexia, diarrhea, nausea, vomiting, drug-induced hepatitis.

Hemat: AGRANULOCYTOSIS, hemolytic anemia, thrombocytopenia.

Neuro: dizziness, ataxia, confusion, fatigue, headache, syncope, tremor, vertigo.
Misc: fever.

Interactions ⬆ ⬇

Drug-Drug:

May ↑ risk of QT interval prolongation when used with tricyclic antidepressants, erythromycin, clarithromycin, haloperidol, sotalol, or fluoroquinolones.
↑serum digoxin levels and may cause toxicity (dose reduction recommended).
Phenytoin, phenobarbital, carbamazepine, or rifampin may ↑ metabolism and ↓ effectiveness.
Cimetidine, diltiazem, verapamil, amiodarone, ketoconazole, itraconazole, and protease inhibitors↓ metabolism and may ↑ blood levels.
Excretion is delayed and effects ↑ by drugs that alkalinize the urine, including carbonic anhydrase inhibitors, thiazide diuretics, and sodium bicarbonate.
Potentiates the effects of neuromuscular blocking agents and warfarin.
Additive hypotension with antihypertensives, nitrates, and acute ingestion of alcohol.
May ↑ procainamide, haloperidol, mexiletine, or tricyclic antidepressant levels and risk of toxicity.
May antagonize anticholinesterase therapy in patients with myasthenia gravis.
Additive anticholinergic effects may occur with agents having anticholinergic properties (including antihistamines, tricyclic antidepressants).

Drug-Food:

Grapefruit juice↑ serum levels and effect (avoid concurrent use).
Foods that alkalinize the urine (see Appendix M) may ↑ serum quinidine levels and the risk of toxicity.

Route/Dosage ⬆ ⬇

Quinidine Gluconate (62% Quinidine)

PO (Adults): 324–972 mg q 8–12 hr.

Quinidine Sulfate (83% Quinidine)

PO (Adults): Atrial/ventricular arrhythmias: 200–400 mg q 4–6 hr; may be ↑ to achieve therapeutic response (not to exceed 3–4 g/day).
PO (Children): 6 mg/kg 4–5 times daily.

Availability ⬆ ⬇

(Generic available)

Quinidine Gluconate

Extended-release tablets: 324 mg;

Quinidine Sulfate

Tablets: 200 mg; 300 mg;
Extended-release tablets: 300 mg;
In combination with: dextromethorphan (Nuedexta); see Appendix [not included in this PDA edition].

Assessment ⬆ ⬇

Monitor ECG, pulse, and BP periodically during therapy.

Lab Test Considerations:

Monitor hepatic and renal function, CBC, and serum potassium and magnesium levels periodically during prolonged therapy.

Toxicity and Overdose:

Serum quinidine levels may be monitored periodically during dose adjustment. Therapeutic serum concentrations are 2–6 mcg/mL. Toxic effects usually occur at concentrations >8 mcg/mL.
- Signs and symptoms of toxicity or cinchonism include tinnitus, hearing loss, visual disturbances, headache, nausea, and dizziness. These may occur after a single dose.
- Cardiac signs of toxicity include QRS widening, cardiac asystole, ventricular ectopic beats, idioventricular rhythms (ventricular tachycardia, ventricular fibrillation), paradoxical tachycardia, and torsades de pointes.

Implementation ⬆ ⬇

Do not confuse quinidine with quinine.
PO: Administer with a full glass of water on an empty stomach either 1 hr before or 2 hr after meals for faster absorption. If GI irritation becomes a problem, may be administered with or immediately after meals. Extended-release preparations should be swallowed whole; do not break, crush, or chew.

IV Administration:

IV: Use only clear, colorless solution.
Intermittent Infusion: Dilute 800 mg of quinidine gluconate (10 mL) in 50 mL of D5W. Infusion is stable for 24 hr at room temperature or 48 hr if refrigerated.16 mg/mL.
Rate: Administer quinidine gluconate at a rate not to exceed 0.25 mg/kg/min. Administer via infusion pump to ensure accurate dose. Rapid administration may cause peripheral vascular collapse and severe hypotension.
Y-Site Compatibility:
- alemtuzumab
- amikacin
- anidulafungin
- argatroban
- atropine
- benztropine
- bleomycin
- bumetanide
- buprenorphine
- butorphanol
- calcium gluconate
- carmustine
- caspofungin
- chlorpromazine
- cisplatin
- cyanocobalamin
- cyclosporine
- dactinomycin
- daunorubicin hydrochloride
- dexrazoxane
- digoxin
- diltiazem
- diphenhydramine
- dobutamine
- docetaxel
- dopamine
- doxorubicin liposomal
- doxycycline
- enalaprilat
- ephedrine
- epinephrine
- epoetin alfa
- erythromycin
- esmolol
- famotidine
- fentanyl
- fluconazole
- fludarabine
- gemcitabine
- gentamicin
- glycopyrrolate
- granisetron
- hydromorphone
- idarubicin
- imipenem/cilastatin
- irinotecan
- isoproterenol
- labetalol
- leucovorin
- lidocaine
- linezolid
- lorazepam
- magnesium sulfate
- mannitol
- meperidine
- mesna
- methadone
- metoclopramide
- metoprolol
- metronidazole
- milrinone
- mitomycin
- mitoxantrone
- morphine
- moxifloxacin
- multivitamins
- mycophenolate
- nalbuphine
- naloxone
- nitroglycerin
- norepinephrine
- octreotide
- ondansetron
- oxaliplatin
- paclitaxel
- palonosetron
- pamidronate
- papaverine
- pentamidine
- phenylephrine
- phytonadione
- potassium acetate
- potassium chloride
- procainamide
- prochlorperazine
- promethazine
- propranolol
- protamine
- pyridoxine
- succinylcholine
- sufentanil
- tacrolimus
- theophylline
- thiamine
- thiotepa
- tirofiban
- tobramycin
- topotecan
- vancomycin
- vasopressin
- verapamil
- vinblastine
- vinorelbine
- voriconazole
- zoledronic acid
Y-Site Incompatibility:
- acyclovir
- aminophylline
- amiodarone
- amphotericin B deoxycholate
- emphotericin B lipid complex
- ampicillin
- ampicillin/sulbactam
- aztreonam
- bivalirudin
- cefazolin
- cefotaxime
- cefotetan
- cefoxitin
- ceftazidime
- ceftriaxone
- cefuroxime
- chloramphenicol
- clindamycin
- dacarbazine
- dantrolene
- daptomycin
- dexamethasone
- ertapenem
- foscarnet
- fosphenytoin
- furosemide
- ganciclovir
- hydrocortisone
- indomethacin
- insulin
- ketorolac
- methylprednisolone
- nafcillin
- nitroprusside
- oxacillin
- pantoprazole
- pemetrexed
- penicillin G
- pentobarbital
- phenobarbital
- phenytoin
- piperacillin/tazobacatam
- sodium bicarbonate
- sulfamethoxazole/trimethoprim

Patient/Family Teaching ⬆ ⬇

Instruct patient to take medication around the clock, exactly as directed, even if feeling well. Take missed doses as soon as remembered if within 2 hr; if remembered later, omit. Do not double doses.
Instruct patient or family member on how to take pulse. Advise patient to report changes in pulse rate or rhythm to health care professional.
May cause dizziness or blurred vision. Caution patient to avoid driving or other activities requiring alertness until response to medication is known.
Inform patient that quinidine may cause increased sensitivity to light. Dark glasses may minimize this effect.
Advise patient to inform health care professional of medication regimen prior to treatment or surgery.
Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and consult health care professional before taking any new medications.
Advise patient to consult health care professional if symptoms of cinchonism, rash, or dyspnea occur or if diarrhea is severe or persistent.
Advise patient to carry identification at all times describing disease process and medication regimen.
Advise female patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.
Emphasize the importance of routine follow-up exams to monitor progress.

section name header

Pronunciation ⬇

Classifications ⬆ ⬇

Indications ⬆ ⬇

Action ⬆ ⬇

Pharmacokinetics ⬆ ⬇