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The myth of incompatibility of gentamicin and heparin revisited
1Division of Nephrology, Department of Internal Medicine, Saint Louis University School of Medicine, Saint Louis, Missouri, USA. bastanib@slu.edu
Introduction:
Earlier reports indicated that gentamicin should not be mixed with heparin due to precipitation and drug mixture incompatibility. With the recent increased interest in antibiotic lock technique for prophylaxis or adjuvant therapy for hemodialysis catheter-associated infections, it became prudent to reexamine the issue.
Method:
A mixture of gentamicin (100 µg/mL) and heparin (5,000 U/mL) in normal saline was stored for up to 4 weeks at 4ºC. Gentamicin concentration and bactericidal and anticoagulant activities were measured for up to 4 weeks of storage.
Results:
The mixture did not show any turbidity or precipitation after fresh preparation, at 48 hours or 4 weeks of storage at 4ºC. Gentamicin concentration (mean ± SD) was 89 ± 7.5 µg/mL, 87 ± 1.0 µg/mL and 85 ± 3.0 µg/mL; gentamicin bactericidal activity was at 1:256 ± 0, 1:256 ± 0 and 1:213 ± 74 dilutions, after fresh preparation, at 48 hours or 4 weeks of storage at 4ºC, respectively (p=NS). Heparin anti-Xa activity was 7,500 ± 990 U/mL and 6,700 ± 707 U/mL, fresh mixture vs. after 4 weeks of storage at 4ºC, respectively (p=NS).
Conclusion:
In our in vitro experiments we showed that a mixture of gentamicin (100 µg/mL) and heparin (5,000 U/mL) in normal saline retained its gentamicin concentration, bactericidal activity and anticoagulant activity for up to 4 weeks of storage at 4ºC. We also present a brief review of the literature on this subject.
Insights
Gentamicin and heparin mixtures are stable for up to 4 weeks at 4°C, retaining antibiotic and anticoagulant properties. This finding supports their use in hemodialysis catheter lock solutions for infection prevention.
Area of Science:
- Pharmacology
- Infectious Diseases
- Nephrology
Background:
- Previous studies advised against mixing gentamicin and heparin due to potential precipitation and incompatibility.
- The antibiotic lock technique for hemodialysis catheters has increased interest in antibiotic-heparin mixtures.
Purpose of the Study:
- To re-evaluate the compatibility and stability of gentamicin-heparin mixtures for potential use in hemodialysis catheter lock solutions.
Main Methods:
- A mixture of gentamicin (100 µg/mL) and heparin (5,000 U/mL) in normal saline was prepared.
- The mixture was stored at 4°C for up to 4 weeks.
- Gentamicin concentration, bactericidal activity, and heparin anticoagulant activity were assessed at intervals.
Main Results:
- No turbidity or precipitation was observed in the gentamicin-heparin mixture during 4 weeks of storage at 4°C.
- Gentamicin concentration and bactericidal activity remained stable throughout the storage period.
- Heparin anti-Xa activity showed no significant change after 4 weeks of storage.
Conclusions:
- In vitro experiments demonstrate that gentamicin and heparin mixtures are stable for up to 4 weeks at 4°C.
- The mixture retains its gentamicin concentration, bactericidal efficacy, and anticoagulant properties.
- This stability supports the potential use of gentamicin-heparin solutions in antibiotic lock techniques for hemodialysis.
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