A controlled action mixing vial (2) includes an elongate mixing container (14) having a movable piston (18) and fluid pressure rupturable seal (20). One pharmaceutical (58) is housed within the mixing container between the seal and the piston. A supplemental container (28) is coaxially translatably mounted to the mixing container and contains a second pharmaceutical (62) between the mixing and supplemental containers. Collapsing the mixing and supplemental containers causes the rupturable seal to open permitting the second pharmaceutical to be driven into the mixing container to drive the piston along the mixing container. The mixing and supplemental chambers are threadably coupled (10, 32) so the mixing is accomplished in a controlled, slow manner.