Quinidex, also known as quinine sulfate, is a medication used to treat abnormal heartbeats, such as arrhythmias. Some common synonyms for quinidex include quinora, kinase, quinidine, and cardioquin. These medications are all used to regulate heart rhythm and prevent serious heart conditions such as atrial fibrillation or atrial flutter. They work by blocking specific electrical signals in the heart, which helps to regulate the heart's rhythm. Although these medications can be effective, they can also have serious side effects, such as nausea, vomiting, and dizziness, so they should only be used under the guidance of a doctor.