Syringe devices and methods for mixing and administering medication

A method of preparing a medication agent for administration to an individual, comprising:

• providing a syringe device comprising a syringe barrel having a forward end that is capped and a piston disposed at an initial position relative to the syringe barrel, the piston having a first end within the syringe barrel, an opposing second end, and having a unitary fluid passageway passing longitudinally through the piston, through the first end and through the second end;
• providing a first component of a medicant within the syringe barrel;
• providing a second component of a medicant within a vial disposed within a vial housing associated with the second end of the piston;
• providing a valve associated with the fluid passageway, the fluid passageway providing fluid communication between the vial and the syringe barrel, the valve being initially provided in a closed position blocking fluid passage through the passageway;
• repositioning the valve to allow fluid passage between the vial and the syringe barrel;
• after repositioning the valve, sliding the piston in a first direction to join the first component with the second component within the vial;
• mixing the first and second components to produce the medication agent by repeated sliding of the piston in opposing directions;
• and
• drawing the medication agent into the syringe barrel, the syringe device being administration-ready through the first end of the syringe without removal of the vial from the device.