If you have one or more fainting spells, notify your doctor at once. Use Quinidex Extentabs cautiously if you have kidney or liver disease. Your doctor will check your blood count and liver and kidney function periodically during long-term therapy. There have been cases of liver damage due to quinidine sensitivity. If you develop an unexplained fever, especially when you begin taking quinidine, your doctor will monitor your liver function for the first 4 to 8 weeks of therapy.
Symptoms usually disappear when quinidine is stopped.
There have been rare cases of severe allergic reaction to quinidine, especially during the first few weeks of therapy. Discuss any allergic reactions you have experienced with your doctor. Do not confuse Quinidex with quinine, which although related, is used to treat nighttime leg cramps and malaria. Your doctor may need to reduce the amount of digoxin you take. If Quinidex Extentabs are taken with certain other drugs, the effects of either could be increased, decreased, or altered.