system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Drug directly acting on blood vessels is:
assistant
The correct answer is  Ref:KDT 6/e p547 Some drugs used to treat hypeension, such as calcium channel blockers -- which prevent calcium from entering blood vesselwalls -- also dilate blood vessels. But the vasodilators that work directly on the vessel walls are hydralazine and minoxidil.