An insert for a luer-type catheter connection includes a fluid pathway connecting a female end and a male end. The male end is configured for slidable insertion into a female luer fitting of a catheter, and the female end is configured to receive a male luer nozzle of a fluid delivery device. The insert also includes a threaded collar having internal threading faced for coupling with the female luer fitting and external threading faced for coupling with a locking collar on the fluid delivery device. A cartridge located in the fluid pathway is configured to hold a patency agent and further to release the patency agent into the catheter when fluid is passed through the cartridge.
