ORAL Pentasa can give you ringing in the ears. Rectal Pentasa wouldn't if I understand things correctly.
Rowasa will work better because it's a 4g dose instead of a 1g dose maybe?
Are you taking flax seed oil by any chance? I think this can reduce clotting factors. Have you had your clotting factors tested? There's also a problem with clotting factors linked to malabsorption typical of Crohn's disease.