A switch operated therapeutic agent delivery device is described. The device comprises two parts, which are assembled by a user prior to use. A first part contains a power supply and circuitry for the device; and a second part comprises electrodes and reservoirs containing the therapeutic agent to be delivered. The action of combining the two parts of the device causes the two parts to be irreversibly coupled together, completes an electrical connection between the two parts, and closes one or more switches, thereby connecting a power source, such as a battery, into the device's circuitry, thereby powering the device on so that it is ready for use. The device can then be attached to a patient, who can operate the device by pressing a button in a proper sequence.