Drugs for the treatment of peripheral vasospasm, there are nitrate ester drugs, such as nitroglycerin, phentolamine. Nitrate drugs dilate peripheral spasm of blood vessels, mainly after the action of the body will be metabolized and produced as nitric oxide, nitric oxide has a dilation of peripheral blood vessels, improve the role of vasospasm. Phentolamine is an α-blocker, by blocking the cytosolic binding of α1 and α2 receptors in the blood vessels, because of the cause of vasodilatation and lower blood pressure. It can also antagonize the vasoconstrictor response induced by norepinephrine and epinephrine, directly relaxing the vascular smooth muscle, causing vasodilation and lowering blood pressure.