What are the side effects of quinidine gluconate?

Common side effects of quinidine gluconate include diarrhea, loss of appetite, muscle weakness, nausea, or vomiting. These side effects are not serious, and only require medical attention if they do not go away or suddenly worsen. Quinidine gluconate may cause serious side effects, including allergic reaction. If you experience signs of an allergic reaction, such as swelling, hives, and difficulty breathing, seek immediate medical attention. You should talk to your doctor if you experience any of these rare but serious side effects: ringing in the ears, changes in vision, dizziness, fainting, a rapid heartbeat, headache, or yellowing of the skin or eyes. Quinidine gluconate may cause unexpected side effects that are not described above. If you experience an unanticipated reaction while taking quinidine, talk to your doctor.