REFLUDAN [lepirudin (rDNA) for injection] is a highly specific direct inhibitor
of thrombin. Lepirudin, (chemical designation: [Leu1, Thr2]-63-desulfohirudin)
is a recombinant hirudin derived from yeast cells. The polypeptide composed
of 65 amino acids has a molecular weight of 6979.5 daltons. Natural hirudin
is produced in trace amounts as a family of highly homologous isopolypeptides
by the leech Hirudo medicinalis. The biosynthetic molecule (lepirudin)
is identical to natural hirudin except for substitution of leucine for isoleucine
at the N-terminal end of the molecule and the absence of a sulfate group on
the tyrosine at position 63.
The activity of lepirudin is measured in a chromogenic assay. One antithrombin
unit (ATU) is the amount of lepirudin that neu-tralizes one unit of World Health
Organization preparation 89/588 of thrombin. The specific activity of lepirudin
is approximately 16,000 ATU/mg. Its mode of action is independent of antithrombin
III. Platelet factor 4 does not inhibit lepirudin. One molecule of lepirudin
binds to one molecule of thrombin and thereby blocks the thrombogenic activity
of thrombin. As a result, all thrombin-dependent coagulation assays are affected,
eg, activated partial thromboplastin time (aPTT) and prothrom-bin time (PT /INR)
values increase in a dose-dependent fashion (Roethig 1991).
REFLUDAN (lepirudin) is supplied as a sterile, white, freeze-dried powder for injection
or infusion and is freely soluble in Sterile Water for Injection USP or 0.9%
Sodium Chloride Injection USP.
Each vial of REFLUDAN contains 50 mg lepirudin. Other ingre-dients are 40 mg
mannitol and sodium hydroxide for adjust-ment of pH to approximately 7.
What are the possible side effects of lepirudin (Refludan)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- sudden numbness or weakness, especially on one side of the body;
- sudden headache, confusion, problems with vision, speech, or balance;
- pain or swelling in one or both legs;
- any bleeding that will not stop;
- black, bloody, or tarry stools;
- coughing up blood or vomit that looks like coffee...
Read All Potential Side Effects and See Pictures of Refludan »
Last reviewed on RxList: 7/31/2007
This monograph has been modified to include the generic and brand name in many instances.