A mechanical dilatation and medicament delivery device for enlarging a flow passage of a vessel by dilating and delivering a therapeutic agent or medicament to an obstruction in the vessel. The present invention comprises a substantially cylindrically shaped expansion member and includes a means engaged to the expansion member for altering the distance between the proximal end and the distal end of the expansion member thereby transforming the expansion member between a diametrically contracted configuration to diametrically expanded configuration. A therapeutic agent or medicament is coated on either the expansion member, or incorporated into a substrate coated on the expansion member.The present method comprises the steps of advancing the coated expansion member to the obstruction in a vessel and applying opposed forces on said expansion member in an axial direction to move the expansion member to an expanded configuration wherein the expansion member dilates the obstruction and the expansion member either passively or actively delivers a therapeutic agent or medicament to the obstruction.