They don't appear to be very different, as far as the clotting factors they affect (see below from wikipedia on each). Also, something on the history of the name warfarin.
Phenprocoumon (marketed under the brand names Marcoumar, Marcumar and Falithrom) is an anticoagulant drug, a derivative of coumarin. It is a vitamin K antagonist that inhibits coagulation by blocking synthesis of coagulation factors II, VII, IX and X. It is used for the prophylaxis and treatment of thromboembolic disorders (thrombosis/pulmonary embolism).
Phenprocoumon inhibits vitamin K reductase.[1]
And
(on warfarin):
Warfarin inhibits the vitamin K-dependent synthesis of biologically active forms of the calcium-dependent clotting factors II, VII, IX and X, as well as the regulatory factors protein C, protein S, and protein Z.[2][26] Other proteins not involved in blood clotting, such as osteocalcin, or matrix Gla protein, may also be affected.
Warfarin is a synthetic derivative of dicoumarol, a 4-hydroxycoumarin-derived mycotoxin anticoagulant originally discovered in spoiled sweet clover-based animal feeds. Dicoumarol, in turn, is derived from coumarin, a sweet-smelling but coagulation-inactive chemical found naturally in sweet clover and many other plants. The name warfarin stems from its discovery at the University of Wisconsin, incorporating the acronym for the organization which funded the key research (WARF, for Wisconsin Alumni Research Foundation) and the ending -arin, indicating its link with coumarin.
