Before starting this drug, the manufacturer recommends that you take a test dose (usually a smaller amount than your regular dose) to determine whether you are allergic to it. Consult your doctor or pharmacist for details.
Take this medication by mouth with or without food with a full glass of liquid (8 ounces/240 milliliters) as directed by your doctor. This medication is best taken on an empty stomach, but taking it with food may help decrease stomach upset. Do not lie down for 10 minutes after taking this medication.
Do not crush or chew extended-release tablets. Doing so can release all of the drug at once, increasing the risk of side effects. Also, do not split the tablets unless they have a score line and your doctor or pharmacist tells you to do so. Swallow the whole or split tablet without crushing or chewing.
There are different brands and forms of this medication available. Not all have identical effects. Do not change quinidine products without talking to your doctor or pharmacist.
Dosage is based on your medical condition and response to treatment. If you are taking regular-release quinidine for an irregular heartbeat, the manufacturer recommends that you take no more than 4 grams daily.
Avoid eating grapefruit or drinking grapefruit juice while being treated with this medication unless your doctor instructs you otherwise. Grapefruit juice can change the amount of certain medications in your bloodstream. Consult your doctor or pharmacist for more details.
Avoid large changes in your dietary salt intake while being treated with this medication unless your doctor instructs you otherwise. The amount of salt in your diet may affect the amount of quinidine absorbed by your system. Consult your doctor or pharmacist for more details.
Use this medication regularly to get the most benefit from it. To help you remember, take it at the same time(s) each day.
Tell your doctor if your condition does not improve or if it worsens.