A blister and package system (1) made of a blister card (3) and an outer package (5) with unique interacting locking mechanisms (23). The blister card is inserted in the outer package and locks immediately without having to further process the outer package or the blister card. The user is able to expose the blisters from the outer package by disengaging the lock. The blister card includes a formable, pliable sheet material (7), into which one or more individual cavities or blisters (9) are formed. The separated cavities are loaded with product (11) and sealed with one or more layers of puncturable or tearable sheet material, such as aluminum foil (13). The blister card contains a stop (21), which may be one or more additional cavities that form an interference mechanism, or an interference blister cavity. The interference blister is trapped by a locking mechanism and stopped by a catch flap (41) included in the outer package.