A rapid exchange catheter extends from a proximal portion which remains outside of a patient's body during use to a distal portion which, during use, is located within a body lumen adjacent to a target area to be treated, wherein the proximal and distal portions are coupled by a medial portion. The catheter comprises a guide wire lumen extending longitudinally through the distal portion and a guide wire receiving channel formed by an outer surface of the medial portion, wherein the guide wire lumen is open to a distal end of the channel.