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Quinidine

Natisedine, Quinicardine · ATC code C01BA01

Also known as: Chinidin, Kinidin

Key facts
Active substance
Quinidine
ATC code
C01BA01
Authorisation
authorised nationally; no central EU authorisation
Information as of
2026-10-29

Key facts

Quinidine (as quinidine sulfate) is, per the US prescribing information, a class IA antiarrhythmic for atrial fibrillation/flutter and life-threatening ventricular arrhythmias, and for severe P. falciparum malaria.

What it is used for

  • Restoring sinus rhythm in symptomatic atrial fibrillation/flutter when rate control is insufficient.
  • Reducing relapse into atrial fibrillation/flutter in selected high-risk patients when alternatives are inadequate.
  • Suppression of documented life-threatening ventricular arrhythmias.
  • Life-threatening Plasmodium falciparum malaria (part of a regimen centred on quinidine gluconate injection).

Dosing

  • Initiation and dose changes, especially in structural heart disease, should generally be done where monitoring and resuscitation are available.
  • Relapse prophylaxis: start with 200 mg (equivalent to 166 mg of quinidine base) every six hours; increase cautiously only if well tolerated and levels are within the therapeutic range.
  • Conversion: one reported regimen starts with 400 mg every six hours – see the full text.
  • Reduce or stop if QRS or QTc widen to 130% of baseline (QTc then longer than 500 ms), P waves disappear, or tachycardia, bradycardia or hypotension develop.
  • Renal or hepatic dysfunction and heart failure require lower doses.

Contraindications

  • Allergy to quinidine, or thrombocytopenic purpura during prior quinidine or quinine therapy.
  • Rhythm dependent on a junctional or idioventricular pacemaker (e.g. complete AV block) without a functioning artificial pacemaker.
  • Conditions adversely affected by anticholinergic agents, e.g. myasthenia gravis.

Important warnings

  • Increased mortality: in meta-analyses of relapse prevention in atrial fibrillation, more than three times that of placebo.
  • QTc prolongation with risk of torsades de pointes, increased by bradycardia, hypokalemia and hypomagnesemia.
  • Paradoxical increase in ventricular rate in atrial flutter/fibrillation; marked bradycardia in sick sinus syndrome.
  • Caution in patients at high risk of complete AV block.

Side effects

  • Most frequent are gastrointestinal: in one study diarrhea 35%, upper gastrointestinal distress 22%, lightheadedness 15%, headache 7%, fatigue 7%, palpitations 7%.
  • Cinchonism: tinnitus, hearing loss, vertigo, visual disturbances, headache, confusion, delirium – usually a sign of chronic toxicity.
  • Others: rash, visual problems, tremor.

Interactions

  • Digoxin: levels may be as much as doubled; digoxin doses usually need reduction.
  • Warfarin: anticoagulant effect is potentiated.
  • Amiodarone, cimetidine, ketoconazole, diltiazem and verapamil raise quinidine levels; phenobarbital, phenytoin and rifampin lower them; urine-alkalinizing drugs reduce its elimination.
  • Quinidine inhibits P450IID6 and raises levels of drugs metabolized by it.

Pregnancy and breastfeeding

  • There are no adequate studies in pregnant women; give only if clearly needed.
  • Quinidine is present in human milk at levels slightly lower than in maternal serum.

Summary of the official product information, written with AI on 2026-10-29. Every number was checked automatically against the original text. Not reviewed by a physician – the full official text is authoritative.

Full official text →

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For patients

Patient information (US)

This product has no separate US patient information.

Authorisation and brand names by country

Medicines with exactly this active-substance composition, as listed in the national registers – alphabetical and without ranking. Whether a product is currently available is not shown here.

Turkey

  • NatisedineADİLNA İLAÇ SAN. VE TİC. A.Ş. · 1 register entry
  • QuinicardineADİLNA İLAÇ SAN. VE TİC. A.Ş. · 1 register entry

Source: TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, as of 2026-10-16

Brand names in 3 more European countries
Hungary
Chinidin-Wagner
Netherlands
Kinidinesulfaat Teva
Romania
Chinidina

EMA – Article 57 product data (EU/EEA), 2026-10-29

Medelix receives no money from pharmaceutical companies. Brand names are listed alphabetically and without ranking.

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Sources

  1. U.S. Food and Drug Administration. QUINIDINE SULFATE (EPIC PHARMA, LLC) – Prescribing Information, 2023-11-08. DailyMed (NLM), 2026-10-29. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=b0d6341b-d880-4f0b-8844-bc788c03004a
  2. TİTCK – Ruhsatlı Beşeri Tıbbi Ürünler Listesi, 2026-10-16. https://www.titck.gov.tr/dinamikmodul/85

Editorial: Medelix editorial team · last updated 2026-10-29 · How these pages are made · Report an error

Source: U.S. Food and Drug Administration (FDA), prescribing information, via DailyMed (NLM); public domain. Not advertising, not a treatment recommendation. For questions about your own treatment, ask your doctor or pharmacist.