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Antibiotic treatment and associated prolonged prothrombin time.
K J Williams1, R P Bax, H Brown
1ICI Pharmaceuticals, Mereside, Alderley Park, Macclesfield, Cheshire.
Journal of Clinical Pathology
|September 1, 1991
Summary
Cefotetan and similar antibiotics rarely cause prolonged prothrombin times. However, cefotetan significantly increased prothrombin time by over 12 seconds in 3.8% of patients, indicating a potential bleeding risk.
Area of Science:
- Pharmacology
- Clinical Medicine
- Hematology
Background:
- Antibiotics, particularly cephalosporins, can interfere with hemostasis.
- N-methyl-thiotetrazole (NMTT) side chain is implicated in vitamin K antagonism.
- Prolonged prothrombin time (PT) is a marker for coagulation defects.
Purpose of the Study:
- To compare the incidence of prolonged PT and bleeding episodes between cefotetan and equivalent antibiotics.
- To identify risk factors associated with PT prolongation in patients receiving these antibiotics.
Main Methods:
- Multicentre study involving 1109 patients.
- Patients received either cefotetan or comparable antibiotics.
- Incidence of prolonged PT (>12 seconds) and clinical bleeding were recorded and analyzed.
Main Results:
- No significant difference in overall prolonged PT incidence (9.9% cefotetan vs. 8.0% comparators).
- Significantly higher incidence of PT increases >12 seconds with cefotetan (3.8%) versus comparators (0.8%).
- Risk factors for PT increase included surgery, older age, high platelets, low albumin, and elevated urea/creatinine.
Conclusions:
- While overall PT prolongation is similar, cefotetan poses a higher risk for significant PT increases.
- All antibiotic treatments can affect hemostasis.
- Thorough assessment of new antibiotics in large studies is crucial to define clinical significance of hemostatic defects.