In-vitro studies on drug antibiotic interactions: III Anticoagulants

The antimicrobial effect of some anticoagulants were tested. All drugs showed no antimicrobial activity against the tested organisms. The effect of the chosen drugs when combined with a selected number of antibiotics wes studied on Staphylococcus aureus and Escherichia coli to determine the type of interaction. Most anticoagulants showed either antagonism or no effect. However, few exhibited synergistic effect. Preliminary studies using electronic absorption spectrometry indicated that some sort of physical interaction have occurred between some anticoagulants and tetracyclines. The infrared spectra showed some differences and deviations which may be taken as criterion for association between phenindione and doxycycline