Safety quick-refill compact pump for administering drugs, comprising: - a motor-driven electromechanical actuator electronically controlled by a programmable electronic unit and adapted to cause bi-directional axial sliding of an extendable sliding rod which at least partially protrudes from a casing enclosing said actuator and carries at its head a pusher adapted to cause axial sliding of a plunger of a cylindrical reservoir or container containing a liquid drug and equipped, at an end thereof, with a pierceable membrane, said actuator being further externally provided with a first connecting portion of a male-female connecting joint (23,25) at least partially surrounding said sliding rod; - an elongated cylindrical container provided with a second connecting portion of said male-female connecting joint (23,25) and firmly associatable to the actuator by means of said second, complementary connecting portion, and defining, at its inside, a cylindrical chamber axially extending about the sliding axis of the sliding rod when said actuator and container are associated with each other, and arranged to receive within it said cylindrical reservoir, said container being provided, at a first end thereof, with an opening as inlet for the reservoir and, at its opposite end, with a duct for transporting the drug contained within the reservoir to the outside of the container; - a hollow piercing element oriented towards the inside of the chamber and provided with a piercing tip oriented towards the inside of the chamber and defining said duct so that, when the reservoir is housed within the chamber and the container is firmly associated with the actuator by means of the male-female joint (23,25), said piercing element is in fluid communication with the inside of the reservoir, characterized in that said piercing element, said container and said second connecting portion constitute a single inseparable body so that, when the body of the container is firmly associated with the body of the actuator and the reservoir is housed within the container, the piercing element communicates, through the duct, the volume inside the reservoir and the environment outside the container. - a motor-driven electromechanical actuator electronically controlled by a programmable electronic unit and adapted to cause bi-directional axial sliding of an extendable sliding rod which at least partially protrudes from a casing enclosing said actuator and carries at its head a pusher adapted to cause axial sliding of a plunger of a cylindrical reservoir or container containing a liquid drug and equipped, at an end thereof, with a pierceable membrane, said actuator being further externally provided with a first connecting portion of a male-female connecting joint (23,25) at least partially surrounding said sliding rod; - an elongated cylindrical container provided with a second connecting portion of said male-female connecting joint (23,25) and firmly associatable to the actuator by means of said second, complementary connecting portion, and defining, at its inside, a cylindrical chamber axially extending about the sliding axis of the sliding rod when said actuator and container are associated with each other, and arranged to receive within it said cylindrical reservoir, said container being provided, at a first end thereof, with an opening as inlet for the reservoir and, at its opposite end, with a duct for transporting the drug contained within the reservoir to the outside of the container; - a hollow piercing element oriented towards the inside of the chamber and provided with a piercing tip oriented towards the inside of the chamber and defining said duct so that, when the reservoir is housed within the chamber and the container is firmly associated with the actuator by means of the male-female joint (23,25), said piercing element is in fluid communication with the inside of the reservoir, characterized in that said piercing element, said container and said second connecting portion constitute a single inseparable body so that, when the body of the container is firmly associated with the body of the actuator and the reservoir is housed within the container, the piercing element communicates, through the duct, the volume inside the reservoir and the environment outside the container.