Catheter lock solution

Catheter lock solution is a solution put into catheters to fill the catheter when not in use, primarily to prevent clotting. Neutrolin is an anti-microbial catheter lock solution developed by Cormedix/Cormedix GmbH. Neutrolin contains heparin and citrate (1000 U/mL and 3.5% respectively^[1]), two compounds commonly used to prevent thrombosis and maintain catheter patency. Other brand names include Citra-Lock and Taurolock.

Neutrolin also contains taurolidine, an anti-microbial agent that has been shown to be safe and effective in preventing bacterial colonization of catheters.^{[2][3][4][5][6]} No resistance to taurolidine has been observed to date.

To avoid the use of heparin in central venous catheters, citrate catheter locks were developed. Citrate solutions can be used as a catheter lock without any additives like antibiotic agents or antiseptic agents like taurolidine. Antibiotic catheter lock solutions could lead to antibiotic resistance and taurolidine has been associated with catheter-related clotting. Therefore it is necessary to mix taurolidine products with heparin to avoid catheter patency issues like thrombosis.^[7] Heparin is an anticoagulant, and if used as a catheter lock solution it could leak into the blood circulation of the patient. Therefore it has been associated with catheter-related bleeding and heparin induced thrombocytopenia (HIT).^[8][9]

Citrate catheter lock solutions are being used in three different concentrations – 4%, 30% and 46.7%. Citrate catheter lock solutions of 4% concentration have been recommended as best practice in a position statement of European Renal Best Practice guidelines, as published in 2010.^[10]

The concentrations of 30% citrate and 46.7% citrate used as catheter lock solution have been associated with lower rates of catheter related infection and a decrease of the use of thrombolytic agents like urokinase or tissue plasminogen activator (t-PA).^[11][12]

Taurolidine/heparin (Defencath) was approved for medical use in the United States in November 2023.^[13][14]