A two-piece, child-resistant closure device for dispensers of liquid medicaments, the closure device comprising: a dosage cup having a bottom portion having an inner surface and an outer surface, a depending skirt having an inner surface and an outer surface, a plurality of volumetric gradations on the outer surface of the depending skirt, an inner chamber defined by the inner surfaces of the bottom portion and the depending skirt, a plurality of radially inward projecting cap lugs mounted on a perimeter of the inner chamber, and a protrusion on the inner surface of the bottom portion, an open end; the closure device characterised in that it further comprises either: a) a thread-on bottle adapter having a flow restrictor, a plug seal, and a threaded attachment collar, wherein the flow restrictor comprises a centrally located cylindrical stem, a flexible shoulder, and a collection chamber, and wherein the threaded attachment collar comprises an outer surface having a plurality of helical lock grooves complementary to the plurality of cap lugs, an inner surface having a threaded upper portion, and an unthreaded lower portion; or b) a press-in bottle adapter having a flow restrictor, the flow restrictor having a cylindrical stem and a flexible shoulder, a rigid shoulder, and a lower body. a dosage cup having a bottom portion having an inner surface and an outer surface, a depending skirt having an inner surface and an outer surface, a plurality of volumetric gradations on the outer surface of the depending skirt, an inner chamber defined by the inner surfaces of the bottom portion and the depending skirt, a plurality of radially inward projecting cap lugs mounted on a perimeter of the inner chamber, and a protrusion on the inner surface of the bottom portion, an open end; a bottom portion having an inner surface and an outer surface, a depending skirt having an inner surface and an outer surface, a plurality of volumetric gradations on the outer surface of the depending skirt, an inner chamber defined by the inner surfaces of the bottom portion and the depending skirt, a plurality of radially inward projecting cap lugs mounted on a perimeter of the inner chamber, and a protrusion on the inner surface of the bottom portion, an open end; the closure device characterised in that it further comprises either: a) a thread-on bottle adapter having a flow restrictor, a plug seal, and a threaded attachment collar, wherein the flow restrictor comprises a centrally located cylindrical stem, a flexible shoulder, and a collection chamber, and wherein the threaded attachment collar comprises an outer surface having a plurality of helical lock grooves complementary to the plurality of cap lugs, an inner surface having a threaded upper portion, and an unthreaded lower portion; or b) a press-in bottle adapter having a flow restrictor, the flow restrictor having a cylindrical stem and a flexible shoulder, a rigid shoulder, and a lower body. a) a thread-on bottle adapter having a flow restrictor, a plug seal, and a threaded attachment collar, wherein the flow restrictor comprises a centrally located cylindrical stem, a flexible shoulder, and a collection chamber, and wherein the threaded attachment collar comprises an outer surface having a plurality of helical lock grooves complementary to the plurality of cap lugs, an inner surface having a threaded upper portion, and an unthreaded lower portion; or b) a press-in bottle adapter having a flow restrictor, the flow restrictor having a cylindrical stem and a flexible shoulder, a rigid shoulder, and a lower body.