a portable medication delivery system enables a patient to elect slow continuous auto - administration or rapid bolus self - administration of a fluid medication . the medication delivery system has an infusion pump , which includes a fluid storage chamber and a spring - driven piston positioned in the fluid storage chamber . the fluid storage chamber is initially charged with the medication and the infusion pump automatically delivers a continuous dosage of the medication at a first flow rate over a long time from the fluid storage chamber to a treatment site in the patient . a bolus injector is positioned in series or in parallel with the infusion pump and is charged with a bolus dosage of the treatment fluid from the fluid storage chamber for alternate manual self - injection of the medication into the treatment site at a higher second flow rate for a short time . the infusion pump flowpath includes a drip chamber having an in - line flow restriction , which converts a continuous flow stream from the fluid storage chamber to a drip stream . a sight window in the drip chamber permits the user to visually confirm the flow of medication through the infusion pump .