Does Warfarin Cause Swollen Lips And Slurred Speech?

A person that has problems with many meds, side effects - - is it possible for the person to be having an allergic reaction to warfarin? She is 78 yrs old,lips are swollen & speech slurred. We first thought it was the hydrcodone but given her side effects to meds. I'm worried it's the warfarin. She has been on it for 2 weeks since knee replacement. The dosage has been changed 3 times due to her blood being too thick. Could a reaction to the warfarin be that it is thickening her blood instead of thinning it? Also I might add her blood has always been very thin, if she stuck herself with a needle she bled for a good while. Now when they test her blood she doesn't bleed afterward.