Abciximab
Encyclopedia
Abciximab is a glycoprotein IIb/IIIa receptor antagonist manufactured by Centocor
Centocor
Janssen Biotech, Inc., formerly Centocor Biotech, Inc., is a biotechnology company that was founded in Philadelphia in 1979 with an initial goal of developing new diagnostic assays using monoclonal antibody technology....

 and distributed by Eli Lilly
Eli Lilly and Company
Eli Lilly and Company is a global pharmaceutical company. Eli Lilly's global headquarters is located in Indianapolis, Indiana, in the United States...

 under the trade name ReoPro, is a platelet aggregation inhibitor mainly used during and after coronary artery procedures like angioplasty
Angioplasty
Angioplasty is the technique of mechanically widening a narrowed or obstructed blood vessel, the latter typically being a result of atherosclerosis. An empty and collapsed balloon on a guide wire, known as a balloon catheter, is passed into the narrowed locations and then inflated to a fixed size...

 to prevent platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s from sticking together and causing thrombus (blood clot) formation within the coronary artery. It is a glycoprotein IIb/IIIa inhibitor.

While Abciximab has a short plasma half-life, due to its strong affinity for its receptor on the platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s, it may occupy some receptors for weeks. In practice, platelet aggregation gradually returns to normal about 96 to 120 hours after discontinuation of the drug.

Abciximab is made from the Fab
Fragment antigen binding
The fragment antigen-binding is a region on an antibody that binds to antigens. It is composed of one constant and one variable domain of each of the heavy and the light chain. These domains shape the paratope — the antigen-binding site — at the amino terminal end of the monomer...

 fragments of an immunoglobulin that targets the glycoprotein IIb/IIIa receptor on the platelet membrane.

Indications for use

Abciximab is indicated for use in individuals undergoing percutaneous coronary intervention (angioplasty with or without stent placement). The use of abciximab in this setting is associated with a decreased incidence of ischemic complications due to the procedure and a decreased need for repeated coronary artery revascularization in the first month following the procedure.
Research also shows that this drug can be of use for patients with diabetes and chronic renal insufficiency. It is not the appropriate drug of choice if a patient is scheduled for an emergency surgery (i.e., heart surgery) because bleeding time may take about 12 hours to normalize.

Pharmacokinetics

Abciximab has a plasma half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...

 of about ten minutes, with a second phase half-life of about 30 minutes. However, its effects on platelet function can be seen for up to 48 hours after the infusion has been terminated, and low levels of glycoprotein IIb/IIIa receptor blockade are present for up to 15 days after the infusion is terminated.

Side-effects

Many of the side effects of abciximab are due to its anti-platelet effects. This includes an increased risk of bleeding. The most common type of bleeding due to abciximab is gastrointestinal hemorrhage.

Thrombocytopenia
Thrombocytopenia
Thrombocytopenia is a relative decrease of platelets in blood.A normal human platelet count ranges from 150,000 to 450,000 platelets per microliter of blood. These limits are determined by the 2.5th lower and upper percentile, so values outside this range do not necessarily indicate disease...

 is a rare but known serious risk. Abciximab-induced thrombocytopenia can typically be treated with transfusion of platelet
Platelet
Platelets, or thrombocytes , are small,irregularly shaped clear cell fragments , 2–3 µm in diameter, which are derived from fragmentation of precursor megakaryocytes.  The average lifespan of a platelet is normally just 5 to 9 days...

s.
Abciximab induced thrombocytopenia can last for seven days after initial drug administration. Transfusing platelets is the only known treatment and may have limited effectiveness as the drug may also bind to the new platelets.
Platelet counts, which should average 250,000-400,000, can effectively drop to zero.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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