A multiple catheter assembly (100) including a first catheter (110) constructed from a first material and having a first proximal end region (112), a first distal end region (114) terminating in a first distal tip (116), and an outer surface (120) defining at least a first lumen (122) extending longitudinally therethrough between a first distal (118) and a first proximal (111) opening. The first proximal end region (112) is integrally connected to an extension tube (320) constructed from a second material. A second catheter (130) is constructed from the first material and having a second proximal end region (132), a second distal end region (134) terminating in a second distal tip (136), and a second outer surface (140) defining at least a second lumen (142) extending longitudinally therethrough between a second distal (138) and a second proximal (131) opening. The second proximal end region (132) is integrally connected to an extension tube (350) constructed from the second material. The first lumen (122) and the second lumen (142) are independent from each other for facilitating simultaneous flow in opposite directions. The outer surfaces (120, 140) of the first and second catheters are releasably joined for allowing the first and second distal tips (116, 136) to be at least partially longitudinally split from each other.