Clindamycin does not interact with coumadin directly, though clindamycin is shown to cause liver damage, If this is the case the coumadin can increase INR greater than expected..Regards, kindly click ACCEPT if i have answered to your satisfation, a positive feedback and a bonus will be highly appreciated..esolved Question: my mother take coumadin and was given clindamycin for a tooth infection. Her INR is now 4.8. Her dentist told her that the antibiotic should not interact with her coumadin.