A patient controlled liquid drug administration device (10) is provided that enables either or both of a continuous flow of a liquid drug, as well as successive, large- volume boluses thereof, to be self - administered to and by a patient while avoiding bolus refill during bolus delivery or after bolus delivery but before an intake stroke of the pump occurs. The device includes an elongated housing (12) having an axial cavity (18) extending through it with a reciprocating pump (20) mounted at a bottom end (16) thereof. The pump defines a closed internal reservoir (22) and includes a first wall, or seat (24), that is fixed in the cavity, and a second, flexible wall (26) that is axially movable in the cavity in relation to the fixed wall between reservoir- full and reservoir- empty positions. The pump includes an inlet port (28) that is connectable to a source of a pressurized liquid drug by an inlet conduit (32), and an outlet port (30) subcutaneously connectable to the patient by an outlet conduit (34), both conduits extending out the bottom end of the housing. An outlet clamp (138) is mounted in the cavity to move between a closed position constricting the outlet conduit of the pump, thereby preventing the flow of the liquid drug through the outlet conduit, and an open position. An inlet clamp (200) is mounted in the cavity to move between a closed position constricting the inlet conduit and thereby preventing the flow of liquid through it, and an open position disengaged from the inlet conduit, thereby allowing the flow of liquid through it.
