Urinary retention and intravesical hemorrhage following urethral collagen injections in women using warfarin.

Two women on warfarin anticoagulation experienced urinary retention following urethral collagen bulk injections. Both women developed implant site hematomas, with urinary retention and intravesical hemorrhage. One woman was supratherapeutic and the other was therapeutic on warfarin therapy. Both women required transfusion and prolonged catheterization.