Quinidine Tablet: Uses, Side Effects and Interactions

Quinidine is a medication primarily used to treat certain types of irregular heartbeats (arrhythmias) by helping the heart maintain a steady rhythm. It belongs to a group of drugs known as antiarrhythmics.

Quinidine works by affecting the electrical signals in the heart muscle. It is also sometimes used in the treatment of malaria.

What Is Quinidine Tablet?

Quinidine is a medication classified as a class I antiarrhythmic agent. It is derived from the bark of the cinchona tree and is a stereoisomer of quinine. Quinidine works by stabilising the heart's rhythm and is used to treat various irregular heartbeats, such as atrial fibrillation.

Quinidine Uses:

• Heart Arrhythmias: Quinidine is prescribed to treat or prevent irregular heartbeats (arrhythmias), particularly atrial fibrillation. It helps by reducing abnormal electrical signals in the heart, which can improve your ability to carry out normal activities.
• Combination Therapy:It may be used alongside other medications, such as blood thinners (anticoagulants) and beta-blockers, to manage heart conditions and reduce the risk of blood clot formation.

Conditions Quinidine Treat

• Treats certain types of abnormal heart rhythms (arrhythmias), such as atrial fibrillation and ventricular arrhythmias.
• Sometimes used to help maintain a normal heart rhythm after it has been restored.

Secondary Uses of Quinidine

• Occasionally used as part of malaria treatment when other options are unavailable.
• Used in medical studies related to the electrical activity of the heart.

How Does Quinidine Work?

Quinidine works by blocking specific channels in the heart that carry electrical impulses. This helps stabilize the heartbeat and prevent irregular heart rhythms. It affects the electrical activity in heart muscle cells but does not act on hormones or the central nervous system.

Quinidine Dosage

• The dose depends on the condition being treated and the patient's response
• Commonly prescribed doses range from 200 mg to 400 mg taken two to three times daily
• Always take as directed by a healthcare provider

What Should I Do If I Miss a Dose?

• Take the missed dose as soon as you remember
• If it's nearly time for your next dose, skip the missed dose
• Never double the dose to catch up

What Happens If There Is an Overdose?

• Seek immediate medical attention.
• An overdose can cause life-threatening heart rhythm changes and other complications.

Symptoms of Overdose

• Severe dizziness or fainting
• Very slow or irregular heartbeat
• Blurred vision
• Confusion or seizures

Quinidine Side Effects:

Common side effects include diarrhea, nausea, vomiting, fever, heartburn, headache, dizziness, fatigue, weakness, rash, and difficulty sleeping. Serious side effects may include ringing in the ears (tinnitus) and unusual bleeding or bruising.

Common Side Effects

• Nausea
• Vomiting
• Diarrhea
• Dizziness
• Ringing in the ears (tinnitus)

Serious But Rare Side Effects

• Severe allergic reactions (rash, itching, swelling)
• Vision problems or blurred vision
• Low platelet count (bruising, bleeding)
• Severe irregular heartbeats

Precautions:

• Inform your doctor about any allergies and medical history, especially of certain heart conditions, low blood pressure, bleeding disorders, kidney or liver disease, and electrolyte imbalances.
• Quinidine can prolong the QT interval in the heart's electrical cycle, which can increase the risk of serious irregular heart rhythms. This risk is higher if you have certain medical conditions or take other medications that also prolong the QT interval.
• Avoid using quinidine during pregnancy as it may harm the unborn baby. It is also excreted in breast milk, so consult your doctor before breastfeeding.
• Senior adults may be more sensitive to quinidine's side effects, particularly dizziness.
• Do not overdose on quinidine, as it can lead to serious complications. If overdose is suspected, seek medical help immediately.

Possible Interactions with Other Medications (Drug Interactions)

• Quinidine can interact with other heart medications, such as digoxin and amiodarone, increasing the risk of side effects.
• It may affect the way blood thinners like warfarin work, possibly leading to increased bleeding risk.
• Combining quinidine with antidepressants or antipsychotics can increase the risk of irregular heartbeat (QT prolongation).
• Use caution when taking supplements like St. Johns Wort, as it may reduce the effectiveness of quinidine.
• Always inform your doctor about any herbal products or over-the-counter medicines you're using.

How Should Quinidine Be Stored?

• Store at room temperature between 20°C to 25°C (68°F to 77°F).
• Keep away from moisture, heat, and direct sunlight.
• Do not store in the bathroom or near a sink where it might get damp.

What Happens If Quinidine Is Not Stored Properly?

• Exposure to heat, moisture, or light can reduce the effectiveness of the medicine.
• It may lead to the medicine breaking down or becoming unsafe to use.
• Always check the packaging for storage instructions and expiration date.

Quinidine vs Plaquenil:

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