This can be very interesting topic so I will start from the beginning " So God said let it be and it was" LOL .. we all have cascading steps before we make clott. This is good because otherwise we will very fast step six feet under.. So, when we are under the stress god said , ( I like to joke with this God said because by love of mother earth I do not know how else do explain it - Darwin just does not help here) , so He said let us clot because if someone hurt you you need to stop bleeding. That's why we hit clots in hospitals from time to time ( there are other reasons also but this one is kind of most common) . So , smart people discovered heparin , extracted it first from the swine and later made synthetics. It does not stop clotting that is going on at the moment but stops new cascades in I think X and XI steps ( do not cite me one of those steps 1 - 12 for sure
) So , it has very short half life but it works until starts to feel too powerful and decide to wreak a havoc and induce thrombocytopenia which is famous HIT disease BAD, BAD, BAD disease... bleeding going on all around the place. So , people decided to make Low molecular weight heparin or otherwise called Lovenox which is still heparin and is still able to produce HIT but not so often. It is given 1 mg/ kg usually q 12 hours ( that is his half life) , or sometimes 40 mg q day depending on situation and genetics. It is good for pregnant and breastfeeding does not cross placenta. The draw back is MONEY . Expensive and insurance will not cover it easy.. .So then comes in Coumadin most save but still bleeding issues , problems with diet , cheking INR from time to time, and all that. It needs bridge therapy because it does not get right away on track so usually Lovenox is given for 5 - 10 days together with coumadin and then coumadin is left to do the job. It is tricky med. Has very narrow therapeutic level. If it goes lower then needed then it does not work, if it goes more then needed then it works too much
) and pt end up bleeding so it is very fine constant care and education included.
I hope this helps a little bit.