TETRACYCLINES AND WARFARIN AND OTHER ORAL ANTICOAGULANTS

The effects of the anticoagulants are not usually altered to a clinically relevant extent by the concurrent use of tetracyclines, but a few patients have shown increases in anticoagulant effect, and a handful have bled.
The clinical importance of this interaction is unknown, but bear it in mind in case of an excessive response to anticoagulant treatment.