Paquinil is one of the common medications used to treat RA and is usually tolerated very well. All medications have good effects and side effects and some side effects can be very serious, but they are usually rare - if you stayed away from all medication where somebody had died as a complication of a side effect, you wouldn't take any medication at all (come to think of it, there are number of foods you wouldn't do it, either). However, it's important that you feel safe taking the medication you and your doctor have decided is the best choice for you, so ask your rheumatologist about your concern. They may recommend that you pay more attention to getting enough potassium through your diet, perhaps you dietitian or nutritionist for guidance in maintaining a balanced diet and get regular blood tests to monitor the potassium levels in your blood.