<prompt> Which of the following statements about hydralazine is not trueIt causes direct relaxation of blood vesselsIt causes detection of both aerial and venousPostural hypotension is not a common problemIt increases plasma renin activity  <response>: Hydralazine is a predominant aerial dilator that relaxes blood vessels by nitric oxide and opening potassium channels. There is compensatory increase in plasma renin activity with all vasodilators. Postural hypotension is predominantly caused by dilatation of veins and is not a significant feature of hydralazine 