Medical devices, kits, and methods are provided for delivering a fluid containing a drug to a patient. Devices (102, 402, 702) include a housing (104, 404, 704) defining a lumen and an osmotically-driven piston (420) moveable within the lumen. The housing may be elastically deformable between a first shape suitable for insertion through a patient's urethra and a second shape suitable for retention of the device in the patient's bladder.
