Rheumatoid arthritis (RA) is thought to be an autoimmune disease. Your immune system normally makes antibodies to protect you from germs (bacteria and viruses). In people with autoimmune diseases, the immune system makes antibodies that attack the tissues of the body. It is not clear why this happens. Penicillamine belongs to a group of medicines known as disease-modifying antirheumatic drugs (DMARDs) and works by suppressing your immune system. This helps to stop it from attacking the tissues of your body and reduces the damaging effect of the disease on your joints.
This is a companion discussion topic for the original article at https://patient.info/medicine/penicillamine-2