Quinidine is a medication primarily used to treat certain types of irregular heartbeats, known as arrhythmias. It works by stabilizing the electrical activity in the heart, helping to restore a normal rhythm. Quinidine is derived from cinchona bark, which has been used for centuries to treat various ailments. This drug can be administered orally or intravenously and is often prescribed when other treatments are ineffective. While it can be effective, quinidine may cause side effects, including gastrointestinal issues and potential interactions with other medications. Regular monitoring by a healthcare provider is essential during treatment.