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