A decade ago, when hydralazine was used first in the treatment of hypertension, a significant number of patients developed a peculiar reaction that was later identified as the "hydralazine syndrome." The initial symptoms closely mimicked rheumatoid arthritis. The fully developed reaction mimicked the clinical picture of systemic lupus erythematosus (SLE), except for one or possibly two notable differences.
The difference that is most apparent is the absence of renal involvement in the hydralazine syndrome in man. This lack of renal disease is, however, based purely on negative urine findings, in contrast to the positive findings at one stage or another in more than 60% of patients with SLE. There is not enough evidence to rule out the occurrence of renal involvement with finality in this reaction to hydralazine. Renal lesions have been produced by administration of hydralazine in dogs. Also, renal biopsies have revealed that histological changes of SLE may