Methods and devices for preventing fluid flow through the relatively short guidewire lumen of a rapid exchange catheter. The guidewire lumen for a rapid exchange catheter is provided with a narrowed or sealed section allowing for passage of a guidewire therethrough while preventing fluid flow while a guidewire is disposed therethrough. The narrowed or sealed section extends for a relatively short length of the guidewire lumen to avoid creating excessive friction between the guidewire and the guidewire lumen. In several embodiments the narrowed or sealed section is placed proximal of the distal end of the guidewire lumen.