Syringe assemblies (100) having a passive disabling system to prevent reuse are provided. According to one or more embodiments, the syringe assembly comprises a barrel (120), plunger rod (140) and stopper (160) wherein the plunger rod further comprises a locking protrusion (144) that locks the plunger rod within the barrel. Certain embodiments further include a frangible portion (143) on the plunger rod that breaks when reuse is attempted. One or more embodiments include a plunger rod and stopper attachment that prevents disassembly of the syringe assembly prior to use. Syringe assemblies of one or more embodiments also include visual indicators (310) or markers (300) indicating whether a syringe assembly is used or the plunger rod is locked within the barrel.
