This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
One of the following statements about hydralazine is not true - 
Select and explain. 
A. It causes direct relaxation of blood vessels, B. It causes dilatation of both aeries and veins, C. Postural hypotension is not a common problem, D. It increases plasma rennin activity
B: It causes dilatation of both aeries and veins
Answer: B: It causes dilatation of both aeries and veins 
Explanation: Ans. is 'b' i.e., It causes dilatation of both aeries and veins o Hydralation is a potent vasodilator o It acts as a vasodilator by directly acting on aerioles. It has negligible effect on veins. o There is also renin release with secondary salt and water retention. o Postural hypotension is not a prominent action because of little action on veins; venous return and cardiac output are not reduced.