Influence of prazosin on the development of antinuclear antibodies in hypertensive patients.

A recent publication suggested that antinuclear antibodies (ANA) occur in up to one third of patients treated with the hypotensive drug prazosin (Minipress). We have examined a large group of hypertensive patients and found ANA in 9.7% of 145 patients taking prazosin and in 12.2% of hypertensive patients on any treatment regimen. Excluding patients taking methyldopa (a drug associated with a high ANA incidence), the ANA incidence fell to 6.9% in the prazosin-treated group and to 7.2% of all treated hypertensives. Of over 350 untreated hypertensive patients, 6.0% had ANA. Prazosin did not increase the ANA incidence in patients on or off various drug combinations including beta blockers and diuretics. Analysis of the data by age and sex confirmed our conclusion that prazosin therapy is not accompanied by an increase in ANA.