Antibiotic Lock Technique: Review of the Literature

Megan B. Bestul, PharmD; Heather L. VandenBussche, PharmD


Pharmacotherapy. 2005;25(2):211-227. 

In This Article


Clinical trials have evaluated the use of antibiotic lock technique for prevention and treatment of catheter infections, but most of the prevention trials used antibiotic flush solutions rather than true antibiotic lock therapy. Although preventive therapy appears to be successful in inhibiting catheter colonization and, therefore, development of catheter infections, these flush solutions may predispose patients to antibiotic resistance since the solutions are infused systemically as opposed to being contained within a catheter lumen and withdrawn before utilization of the catheter for drug administration. Comparatively, vancomycin used as true lock therapy may select for resistance if CVCs are colonized with intrinsically resistant strains that could overgrow when vancomycin-susceptible organisms are suppressed. In addition, using flush solutions may not result in a high concentration of antibiotic in contact with the catheter lumen for an extended period of time, depending on the frequency of infusions given through the catheter.

In trials evaluating antibiotic lock technique for the treatment of catheter infections, the lock technique resulted in significantly shorter hospital stays compared with systemic antibiotics alone. In addition, no differences were noted in cure rates between antibiotic lock monotherapy and systemic therapy administered before antibiotic lock technique.[43,55] In these small trials, most catheter infections were cured with antibiotic lock technique (with or without systemic antibiotics), but failures were reported, mainly due to infections with other organisms, catheter occlusion or blockage (heparin not included in most trials), or persistence of Candida colonization.[45,47,54,57,62,63,64] In addition, the use of antibiotic lock therapy resulted in average subsequent infection-free periods of 74-152 days.[45,57] The antibiotic lock technique appeared to be less effective in treating infections of implantable ports than infections of other types of CVCs.[61,62]

Limitations of these trials need to be considered when making conclusions regarding antibiotic lock technique in catheter-related sepsis. Data are lacking from large, randomized, controlled trials to determine if antibiotic lock technique is more effective than systemic antibiotics for treatment of line infections. The treatment studies vary in the selection of antibiotics used for the lock technique, as well as in the concentrations and dwell times. In addition, some studies included lock technique in combination with or after systemic antibiotic treatment, which were not randomized; furthermore, the study populations differed significantly and various definitions of catheter-related sepsis were used. None of these studies evaluated antimicrobial blood levels with the lock technique to determine if systemic exposure occurred with this treatment modality.

Based on the available evidence, antibiotic lock technique monotherapy appears effective when treating certain catheter-related infections and can prolong catheter life. Also, antibiotic lock monotherapy may result in shorter hospital stays compared with systemic antibiotic therapy for treatment of line infections. For patients with a catheter-related infection that has not progressed to septicemia and does not involve tissue infection at the insertion or tunnel site, antibiotic lock technique could be considered as an option to salvage venous access when such salvage is a high priority in a patient with limited venous access sites or to avoid adverse effects from systemic antibiotics.