DRUG-INDUCED LUPUS - An inflammatory autoimmune disorder, similar to lupus, that is caused by an adverse reaction to a medication. Drugs that are known to cause this reaction include procainamide, isoniazid, sulfasalazine, hydralazine, methyldopa, phenytoin, chlorpromazine, and penicillamine. The arthritis, cardiac, pulmonary and systemic features may be present, but the kidney involvement (nephritis) and neurologic disease are rare. Symptoms generally resolve spontaneously after stopping the medication. Complications include myocarditis, pericarditis, thrombocytopenic purpura, and infections.