A syringe assembly (100) having a passive disabling system to prevent reuse are provided. According to the embodiment, the syringe assembly comprises a barrel (420), plunger rod (440) and stopper (460) wherein the plunger rod further comprises a flexible protrusion (444) that locks the plunger rod within the barrel. The embodiment further includes a frangible portion (443) on the plunger rod that breaks when reuse is attempted. The embodiment includes a plunger rod and stopper attachment (446) that prevents disassembly of the syringe assembly prior to use. The syringe assembly also includes visual indicators or markers indicating whether a syringe assembly is used or the plunger rod is locked within the barrel.
