title: Prolonged stability of stored vancomycin, gentamicin, and heparin for use in the antibiotic-lock technique.
abstract: The antibiotic-lock technique has been effective in salvaging tunneled catheters in hemodialysis patients with bacteremia. However, a practical concern exists with respect to the stability of the antibiotics and heparin in normal saline, when stored for a prolonged period. Vancomycin, gentamicin, and heparin were diluted in normal saline to a final concentration of 100 microg/ml of each antibiotic and 5000 units/ml heparin. Fresh samples, and samples refrigerated at 4 degrees C for 48 hours, 1 week, 2 weeks, 3 weeks, and 4 weeks, were assayed (in triplicate) for gentamicin and vancomycin concentration and bactericidal activity (Schlichter test) using methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. An anti-Xa activity assay was used for monitoring heparin anticoagulant activity of the fresh samples and samples refrigerated for 2 and 4 weeks. Mean (+/- SD) anti-Xa activity for heparin/vancomycin solution was 7900 +/- 173 u/ml, and for heparin/gentamicin solution was 7467 +/- 751u/ml; both were stable over a 4-week storage period. Mean bactericidal titer for vancomycin was 1:121 +/- 11, and for gentamicin was 1:242 +/- 22; both were stable over a 4-week storage period. Mean vancomycin concentration was 97 +/- 4 microg/ml, and gentamicin concentration was 86 +/- 3 microg/ml; both were stable over a 4-week storage period. Vancomycin and gentamicin in a heparin/saline solution can be stored at 4 degrees C for up to 4 weeks without adversely affecting antibiotic concentration, bactericidal activity, or heparin anticoagulant activity.
authors.affiliation: Division of Nephrology Department of Internal Medicine Saint Louis University School of Medicine Saint Louis, Missouri 63110, USA. bastanib@slu.edu
authors.forename: Bahar
authors.initials: B
authors.lastname: Bastani
authors.forename: Kamal
authors.initials: K
authors.lastname: Amin
authors.forename: Aaron
authors.initials: A
authors.lastname: Herr
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000925:Anticoagulants / Q000008:administration & dosage; D016470:Bacteremia / Q000188:drug therapy / Q000209:etiology; D002408:Catheters, Indwelling / Q000009:adverse effects; D004355:Drug Stability; D005839:Gentamicins / Q000008:administration & dosage*; D006493:Heparin / Q000008:administration & dosage*; D006801:Humans; D066298:In Vitro Techniques; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D006435:Renal Dialysis / Q000009:adverse effects; D013211:Staphylococcus aureus / Q000187:drug effects; D014640:Vancomycin / Q000008:administration & dosage*
chemical_list: D000900:Anti-Bacterial Agents; D000925:Anticoagulants; D005839:Gentamicins; D014640:Vancomycin; D006493:Heparin