Medicine and Health Sciences Commons^™

Ceftriaxone Potentiates Warfarin Activity Greater Than Other Antibiotics In The Treatment Of Urinary Tract Infections, Lindsay M. Saum, Ryan P. Balmat

Scholarship and Professional Work – COPHS

Background: The cephalosporin class has been associated with an increased risk of bleeding among elderly patients receiving warfarin. Urinary tract infections (UTI) are the most prevalent infection in elderly patients.

Objective: To determine the extent of interaction between antibiotics used in the treatment of UTI, particularly specific cephalosporins and warfarin.

Methods: A retrospective chart review was conducted on chronic warfarin patients with a diagnosis of UTI treated with ceftriaxone, a first-generation cephalosporin, penicillin, or ciprofloxacin. The primary outcome was the comparison of the extent of international normalized ratio (INR) change from baseline between each antibiotic group.

Results: The ceftriaxone group …

Drug-Drug Interaction Between Methotrexate And Levetiracetam Resulting In Delayed Methotrexate Elimination, Emily Bain, Ruemu E. Birhiray, David J. Reeves

Scholarship and Professional Work – COPHS

Objective: To report a case of delayed methotrexate (MTX) elimination while receiving concomitant levetiracetam. Case Report: A 46-year-old man with relapsed osteosarcoma of the base of the skull receiving high-dose MTX tolerated his first cycle of MTX with elimination to nontoxic MTX levels (≤0.1 µmol/L) within 90 hours. After hospital discharge, the patient experienced seizures secondary to brain metastasis and started on levetiracetam, which was continued as maintenance therapy. The patient experienced delayed MTX elimination during cycles 2, 3, and 4 while receiving levetiracetam. On average, elimination to nontoxic MTX levels took 130 hours (106-144 hours). Before the fifth cycle …