Syringe assemblies having a passive disabling system to prevent reuse areprovided. According to one or moreembodiments, the syringe assembly (100) comprises a barrel (120), plunger rod(140) and stopper (160) wherein the plunger rodfurther comprises a locking protrusion (144) that locks the plunger rod withinthe barrel. Certain embodiments further include afrangible portion (143) on the plunger rod that breaks when reuse isattempted. One or more embodiments include a plunger rod andstopper attachment that prevents disassembly of the syringe assembly prior touse. Syringe assemblies of one or more embodimentsalso include visual indicators or markers (300) indicating whether a syringeassembly is used or the plunger rod is locked within thebarrel.
