A microneedle injection and infusion apparatus comprising: a housing having a base and a cavity that extends through the base to define an opening in the base, wherein the base of the housing is configured to be positioned toward a skin surface; a microneedle array holder configured to hold a microneedle array and located in the housing, the microneedle array holder movable with respect to the opening in the base of the housing between a retracted position (H 1) in which the microneedle array is recessed within the housing such that the microneedle array does not contact the skin surface when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder, and an extended position (H 2) in which at least a portion of the microneedle array is positioned to contact the skin surface via the opening when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder; a shuttle configured to hold and carry a cartridge, the cartridge defining a reservoir configured to contain an active agent, the shuttle being movable between a first position (S 1) in which the reservoir of the cartridge is not in fluid communication with a fluid path and a second position (S 2) in which the reservoir is in fluid communication with the fluid path; and an actuator movable between a first position (P 1) and a second position (P 2), wherein movement of the actuator to the second position (P 2) releases the shuttle from its first position (S 1) and allows the shuttle to move toward its second position (S 2), and wherein movement of the shuttle toward its second position (S 2) releases the microneedle array holder from the retracted position (H 1) and allows the microneedle array holder to move to the extended position (H 2), wherein at least a portion of the shuttle is configured to hold the actuator in the second position (P 2) after the actuator has been moved to the second position (P 2). a housing having a base and a cavity that extends through the base to define an opening in the base, wherein the base of the housing is configured to be positioned toward a skin surface; a microneedle array holder configured to hold a microneedle array and located in the housing, the microneedle array holder movable with respect to the opening in the base of the housing between a retracted position (H 1) in which the microneedle array is recessed within the housing such that the microneedle array does not contact the skin surface when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder, and an extended position (H 2) in which at least a portion of the microneedle array is positioned to contact the skin surface via the opening when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder; a retracted position (H 1) in which the microneedle array is recessed within the housing such that the microneedle array does not contact the skin surface when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder, and an extended position (H 2) in which at least a portion of the microneedle array is positioned to contact the skin surface via the opening when the apparatus is positioned on the skin surface and the microneedle array is coupled to the microneedle array holder; a shuttle configured to hold and carry a cartridge, the cartridge defining a reservoir configured to contain an active agent, the shuttle being movable between a first position (S 1) in which the reservoir of the cartridge is not in fluid communication with a fluid path and a second position (S 2) in which the reservoir is in fluid communication with the fluid path; and an actuator movable between a first position (P 1) and a second position (P 2), wherein movement of the actuator to the second position (P 2) releases the shuttle from its first position (S 1) and allows the shuttle to move toward its second position (S 2), and wherein movement of the shuttle toward its second position (S 2) releases the microneedle array holder from the retracted position (H 1) and allows the microneedle array holder to move to the extended position (H 2), wherein at least a portion of the shuttle is configured to hold the actuator in the second position (P 2) after the actuator has been moved to the second position (P 2).