Embodiments herein include catheters and methods for the localized treatment of tissues through transcatheter delivery of active agents. In an embodiment, a method herein can include inserting a catheter into the lumen of a blood vessel. The catheter can include an inflatable balloon, a first lumen within the shaft for delivering a fluid to inflate the balloon, an active agent delivery port, and a second lumen disposed within the shaft for delivering the active agent composition through the shaft to the active agent delivery port. The method can include inflating the balloon to at least partially occlude the flow of blood through the blood vessel. The method can include ejecting the active agent composition from the active agent delivery port into the blood vessel. In an embodiment, a catheter for treating a localized region of the body with an active agent composition is included. Other embodiments are also included herein.