A device includes a housing having a first end, a second end, a first cylinder, a second cylinder parallel to the first cylinder, and a channel connecting the first and second cylinders near the second end. A piston is positioned within the first cylinder. A cartridge containing a therapeutic agent is positioned within the second cylinder. A needle hub containing a needle is positioned within the second cylinder between the cartridge and the first end. A septum is positioned at the first end. A fluid is positioned within the first cylinder. When the device is activated, the piston travels toward the second end, forcing some of the fluid to travel from the first cylinder into the second cylinder, forcing the cartridge toward the first end, causing the needle to penetrate the cartridge and the septum, and causing at least some of the therapeutic agent to extrude through the needle
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