Quinidine Gluconate
Pronunciation: (kwin-ih-DEEN GLOO-ko-nate).
- Generic name
- Quinidine gluconate
- Brand names
- Kinidin, Quinidine Sulfate, Kinidin Durules, Cardioquin, Quinidine Gluconate, Quinidine
- Drug class
- Class Ia Antiarrhythmic
Availability and supply rules vary by country
Trade names by country:
Australia: · Full directory
What Quinidine gluconate is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how Quinidine gluconate works
Quinidine gluconate is a Class Ia antiarrhythmic agent that works by blocking fast inward sodium channels during phase 0 of the cardiac action potential, thereby slowing conduction velocity and prolonging the refractory period. It also inhibits potassium channels, further prolonging repolarization and the QT interval. These effects help suppress abnormal electrical activity in the myocardium. (1)
What Quinidine gluconate is used for
Conversion of atrial fibrillation/flutter to normal sinus rhythm
Indicated in patients with symptomatic atrial fibrillation/flutter whose symptoms are not adequately controlled by measures that reduce the rate of ventricular response. (3)
Reduction in frequency of relapse into atrial fibrillation/flutter
Chronic therapy is indicated for some patients at high risk of symptomatic atrial fibrillation/flutter. (3)
Suppression of recurrent, documented, life-threatening ventricular arrhythmias
Such as sustained ventricular tachycardia, that in the judgment of the physician are life-threatening. (3)
Before taking Quinidine gluconate
Do not take / not appropriate for
- hypersensitivity to quinidine or related drugs, complete heart block without a pacemaker, history of quinidine-induced thrombocytopenic purpura, and certain ventricular arrhythmias (e.g., torsades de pointes). (Contraindication) (3)
Tell your clinician about
(3)How to take Quinidine gluconate
- General Instructions: Take Quinidine gluconate exactly as prescribed by your doctor. Do not take more or less than directed. Swallow tablets whole with a full glass of water.. Adult Dosing: Typical oral dose for arrhythmias: 324–648 mg every 8–12 hours, adjusted based on response and blood levels. IV dosing is individualized.. Pediatric Dosing: Dosing in children is based on weight and specific arrhythmia; only use under specialist supervision.. Administration: Take with or without food. Do not crush or chew extended-release tablets. For IV use, administration should be by a healthcare professional.. When To Stop: Do not stop taking Quinidine gluconate suddenly without consulting your doctor, as this may worsen your condition.. Storage: Store at room temperature, away from moisture and heat. Keep out of reach of children.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (3)
Missed dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose. Do not take an extra dose to make up for a missed dose.
Overdose
Symptoms of overdose may include severe dizziness, fainting, irregular heartbeat, seizures, or loss of consciousness. Seek emergency medical attention or call your local poison control center immediately. (3)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Diarrhea, nausea, vomiting, or abdominal cramping
Incidence: Very common — diarrhea alone occurs in roughly one-third of patients and is often the reason for stopping treatment
Cinchonism — ringing in the ears (tinnitus), headache, dizziness, or blurred/disturbed vision
Incidence: Common, particularly at higher doses or blood levels
Fainting, palpitations, a new or worsening irregular heartbeat, or dizziness that could signal a dangerous heart rhythm (including torsades de pointes) — quinidine can itself provoke life-threatening ventricular arrhythmias, especially early in treatment or after a dose increase
(3)Unusual bruising or bleeding, fever, or signs of infection, which can indicate quinidine-induced thrombocytopenia or other blood disorders
(3)Signs of a hypersensitivity reaction — rash, fever, difficulty breathing, or facial/throat swelling
(3)Serious warnings
FDA-labeled mortality warning (checked directly against the current DailyMed label — no formal boxed/black-box warning section exists for quinidine gluconate, but this is prominent WARNINGS-section language) — serious
Symptoms: FDA-labeled mortality warning (checked directly against the current DailyMed label — no formal boxed/black-box warning section exists for quinidine gluconate, but this is prominent WARNINGS-section language): antiarrhythmic drugs like quinidine have not been shown to enhance survival in patients with non-life-threatening arrhythmias and may actually increase the risk of death, particularly in people with structural heart disease. In a controlled trial, quinidine used to help maintain normal rhythm after atrial fibrillation/flutter was associated with a death rate more than 3 times that of placebo. Quinidine can also itself trigger dangerous, sometimes fatal, ventricular arrhythmias (proarrhythmia), especially early in treatment. Your prescriber weighs these risks carefully against the benefit for your specific heart condition.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (3)
May cause serious or life-threatening arrhythmias — serious
Symptoms: May cause serious or life-threatening arrhythmias. Can interact with many other medications. Not recommended in patients with certain heart blocks without a pacemaker. May cause severe allergic reactions in sensitive individuals. Monitor for signs of liver or blood disorders.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (3)
Contraindications recorded in the clinician database — serious
Symptoms: Contraindications recorded in the clinician database: Contraindications include hypersensitivity to quinidine or related drugs, complete heart block without a pacemaker, history of quinidine-induced thrombocytopenic purpura, and certain ventricular arrhythmias (e.g., torsades de pointes). Use with caution in patients with hepatic or renal impairment, myasthenia gravis, G6PD deficiency, or pre-existing conduction abnormalities.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (3)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Quinidine gluconate interacts with many medications, including digoxin, amiodarone, warfarin, and certain antibiotics and antifungals. It may increase the risk of arrhythmias when combined with other drugs that prolong the QT interval. Always inform your healthcare provider of all medicines and supplements you are taking. | (2) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
Quinine, the levorotatory stereoisomer related to quinidine, has been associated with fetal harm (including reports of fetal blindness and congenital deafness) in the published literature. The FDA label states quinidine should be used during pregnancy only when clearly indicated, weighing the risk of the underlying arrhythmia against potential fetal risk — this decision should be made with the clinician managing the pregnancy. (3)
Breastfeeding
The FDA label advises avoiding quinidine, if possible, in women who are breastfeeding. Only very small amounts pass into breast milk, and no adverse effects have been reported in breastfed infants of treated mothers, but avoidance where clinically feasible is still the labeled recommendation — discuss feeding options with the clinician managing your care. (3)
Children
Frequency: Not applicable. Weight Based: Not recommended for pediatric use. Max Daily Dose: Not applicable. Max Single Dose: Not applicable. Age Restrictions: Safety not established in children (3)
Renal_impairment
The FDA label does not give a specific numeric dose adjustment for renal or hepatic impairment, but caution is required in both. About 20% of quinidine is eliminated unchanged by the kidneys, and most of the rest is metabolized and eliminated via the liver (CYP3A4); reduced kidney or liver function slows quinidine's elimination and can lead to toxic drug accumulation if the dose is not reduced. A lower dose, closer monitoring, and blood-level checks may be needed in patients with significant kidney or liver impairment — this is a decision for the treating clinician, informed by kidney and liver function tests. (3)
Hepatic_impairment
The FDA label does not give a specific numeric dose adjustment for renal or hepatic impairment, but caution is required in both. About 20% of quinidine is eliminated unchanged by the kidneys, and most of the rest is metabolized and eliminated via the liver (CYP3A4); reduced kidney or liver function slows quinidine's elimination and can lead to toxic drug accumulation if the dose is not reduced. A lower dose, closer monitoring, and blood-level checks may be needed in patients with significant kidney or liver impairment — this is a decision for the treating clinician, informed by kidney and liver function tests. (3)
Monitoring
(3)Storage
Dispense in a well-closed, light-resistant container with a child-resistant closure. Store tablets at 20-25°C (68-77°F). Injectable quinidine gluconate is stored at 15-30°C; once diluted for IV use it is stable for 24 hours at room temperature or up to 48 hours refrigerated, per hospital protocol.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: Suppression of ventricular arrhythmias / atrial fibrillation-flutter management
Dose summary: Initial dose of 300 mg orally every 8 hours, may be adjusted based on clinical response.
Renal context: The FDA label does not provide a specific numeric dose-adjustment table for renal or hepatic impairment. Approximately 20% of a quinidine dose is eliminated unchanged in the urine, so the drug should be used with caution in renal impairment, with a lower dose considered, especially in severe impairment. Most of the remaining drug is metabolized and eliminated hepatically (principally via CYP3A4); hepatic dysfunction likewise slows elimination. Because either renal or hepatic dysfunction can lead to quinidine accumulation and toxicity if the dose is not reduced accordingly, individualized dose reduction and monitoring (including quinidine blood levels where available) are advised in both settings. (1) (3)
Frequently asked questions
What is Quinidine gluconate used for?
Quinidine gluconate is used to treat and prevent certain abnormal heart rhythms, including atrial fibrillation, atrial flutter, and some ventricular arrhythmias.
How does Quinidine gluconate work?
It works by blocking specific electrical signals in the heart, helping to restore and maintain a normal heart rhythm.
What should I do if I miss a dose?
Take the missed dose as soon as you remember, unless it is almost time for your next dose. Do not take two doses at once.
Can I take Quinidine gluconate with other medications?
Quinidine gluconate can interact with many other medicines. Always check with your doctor or pharmacist before starting new medications.
What are the serious side effects of Quinidine gluconate?
Serious side effects include severe dizziness, fainting, irregular heartbeat, allergic reactions, and signs of liver problems. Seek medical attention if these occur.
Is Quinidine gluconate safe during pregnancy or breastfeeding?
Use during pregnancy or breastfeeding should only occur if clearly needed and prescribed by your doctor. Discuss risks and benefits with your healthcare provider.
How should I store Quinidine gluconate?
Store at room temperature, away from moisture and heat. Keep out of reach of children.
What happens if I take too much Quinidine gluconate?
Taking too much Quinidine gluconate can lead to serious side effects, including severe hypotension, cardiac arrhythmias (like Torsades de Pointes), and central nervous system depression. Symptoms may also include blurred vision, ringing in the ears, and confusion. If you suspect an overdose, seek immediate emergency medical attention. Do not wait for symptoms to worsen.
Can I drink alcohol while taking Quinidine gluconate?
It is generally advisable to avoid or limit alcohol consumption while taking Quinidine gluconate. Alcohol can exacerbate some of the side effects of antiarrhythmic medications, such as dizziness and lightheadedness. Furthermore, alcohol can affect the liver's metabolism of drugs, potentially altering Quinidine gluconate levels in your body and increasing the risk of adverse reactions or reduced efficacy. Always consult your healthcare provider for personalized advice.
Is Quinidine gluconate safe during pregnancy?
Quinidine gluconate's safety during pregnancy is not definitively established, and it is generally categorized as a 'Category C' drug, meaning animal reproduction studies have shown an adverse effect on the fetus, but there are no adequate and well-controlled studies in humans. Therefore, it should only be used during pregnancy if the potential benefit justifies the potential risk to the fetus. Always consult your doctor to discuss the risks and benefits if you are pregnant or planning to become pregnant.
What is the mechanism of action of Quinidine gluconate?
Quinidine gluconate is a Class Ia antiarrhythmic agent that works by blocking fast inward sodium channels during phase 0 of the cardiac action potential, thereby slowing conduction velocity and prolonging the refractory period. It also inhibits potassium channels, further prolonging repolarization and the QT interval. These effects help suppress abnormal electrical activity in the myocardium. (1)
What is the generic name of Quinidine Gluconate?
The generic name is Quinidine gluconate. It is sold under brand names including Kinidin, Quinidine Sulfate, Kinidin Durules, Cardioquin, Quinidine Gluconate, Quinidine.
What class of drug is Quinidine gluconate?
Quinidine Gluconate is classed as: Class Ia Antiarrhythmic.
References
- Quinidine Gluconate for Abnormal Heart Rhythms — Prescribing Information · · accessed 2026-08-07 · source 1
- Clinician-authored medicine record for Quinidine gluconate (MedGuideGlobal medicines database)MedGuideGlobal clinician-authored medicines database (internal) · International · dated 2026 · accessed 2026-08-07 · source 2
- QUINIDINE GLUCONATE extended-release tablets — full prescribing informationFDA DailyMed · United States · dated 2026 · accessed 2026-08-07 · source 3
- QUINIDINE GLUCONATE TABLET, EXTENDED RELEASE [GOLDEN STATE MEDICAL SUPPLY] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 4
- Quinidine — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 5
- Quinidine Gluconate — FDA approval record (Drugs@FDA ANDA089338)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 6
- Quinidine gluconate — RxNorm normalized drug concept (RXCUI 35220)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 7
Brand names by country
Single-ingredient Quinidine gluconate names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.