Abciximab is a Fab fragment of the chimeric human – murine monoclonal antibody 7E3. It binds to the platelet glycoprotein GP IIb/IIIa receptor and blocks the binding of fibrinogen and von Willebrand factor and thus inhibits platelet aggregation .It increases the bleeding time and the activated clotting times and hence reduces the response of platelets to adenosine diphosphate.Vitronectin receptors are involved in proliferative properties of endothelial and smooth muscle cells as well as the procoagulant properties of the platelets .The antibody fragment binds to these vitronectin factors. Abciximab has shown to reduce the risk of acute events in patients with ischemic cardiac conditions. It is used in patients with cardiac ischemia to prevent ischemic complications. It is also used in patients with angina not responding to treatments and as an adjunct to percutaneous cardiac interventions. It prevents the abrupt closure and restenosis of blood vessels that results from percutaneous transluminal coronary angioplasty. It is available as solution for intravenous use. A bolus of 0.25mg/kg is administered intravenously followed by maintenance dose of 5-10 mg/min through continuous infusion for 12-96 hours.
The side effects of the drug are as follows:
It is observed that patients undergoing neurointerventional procedures who received Abciximab developed intracerebral hemorrhages. The exact cause of intracerebral hemorrhages caused by abciximab remains unclear, but it is believed that it is due to the inhibitory effect on platelets that lasts for 48 hours. The other side effects include headache, hyperesthesia, increased sweating, confusion, dizziness, agitation, confusion, muscle contractions, hypertonia, diplopia, and coma. A thorough history related to intracranial conditions must be collected before initiation of therapy with abciximab.
Thrombocytopenia occurs in about 2%- 4% of patients on abciximab. Thrombocytopenia occurs 12- 96 hours after initiation of therapy. The mechanism by which thrombocytopenia occurs is unclear. Findings of case reports suggest that it may be antibody mediated. Antibodies specific to murine sequences were identified in patients with abciximab induced thrombocytopenia .Pseudo thrombocytopenia has been reported as the cause of low platelet counts in patients receiving abciximab. Pseudo thrombocytopenia is the effect of EDTA on the IIb –IIIa complex , which frees the antigenic binding site on GPIIb. IgM antibody binding increases and platelet stat clumping leading to false thrombocytopenia. To prevent confusion between true thrombocytopenia and pseudo thrombocytopenia , blood samples must be collected in three separate tubes containing EDTA , Citrate and heparin. Platelet counts must be assessed 2-4 hours after initiation of the therapy with abciximab and every 24 hours during the maintenance phase of the therapy. The platelet counts will return to normal after 48 hours of cessation of therapy. If true thrombocytopenia persists or worsens, platelet transfusions may be needed. Abciximab also cause minor bleeding like hematuria, spontaneous hematemesis. Major bleeding like intracranial hemorrhage and major organ bleeding has also been reported by patients receiving abciximab. Patients on abciximab must be asked to avoid activities that cause bruising or injury. Instruct the patient not to drive or perform any risky activities that can predispose them to injuries. Strict bed rest and proper positioning is important to prevent bleeding complications. Advise the patient to contact the doctors if they experience nose bleeds, blood in urine, black tarry stools, cough up blood, vomitus that looks coffee color, unusual vaginal bleeding, or bleeding in the eye. Obtain a detailed history about the use of non prescription over the counter drugs, herbal medicines or dietary supplements the patient is using before initiating the therapy as these may possibly interact with abciximab and cause fatal effects. The risk of bleeding significantly increases if it is administered with anticoagulants like heparin , thrombolytic ,NSAIDs ,ticlopidine , however abciximab is used with aspirin and heparin as combination therapy . It is important to monitor the bleeding time and prevent any injury to the patients during such therapies. A decrease in hemoglobin levels are observed due to bleeding. The other hematologic side effects include leukocytosis , anemia , petechiae .When the patient is receiving abciximab it is advisable to avoid I.M injections , venipuncture, use of indwelling catheters , NG tubes and automatic blood pressure cuffs to prevent bleeding . An intermittent I.V access catheter may be inserted for blood sample collections. Arterial punctures must be avoided and if absolutely necessary, then compressible sites only must be utilized .Pressure must be applied on these sites for 30 minutes and then must be secured with a pressure dressing.
Allergic reactions like anaphylaxis are observed in patients receiving abciximab. This occurs due to the formation of human anti- chimeric antibodies (HACA) that produces allergic reactions. This reaction usually appears 14 days after administration of abciximab and peaks at 4-6 weeks. Hypersensitivity reactions must be anticipated and epinephrine, dopamine, theophylline, corticosteroids, and antihistamines must be kept ready for immediate management.
Atrial fibrillation or flutter , bradycardia , embolism , hypotension , peripheral edema, pseudo aneurysm , supraventricular tachycardia , third degree heart block , thrombophlebitis , weak and thread pulse have been observed in patients on abciximab. Studies show that patients with renal dysfunction receiving abciximab are at higher risk of developing cardiac complications.
Abciximab may cause dysphagia, hematemesis, dyspepsia, diarrhea, gastro esophageal reflux, nausea, and vomiting.
Genito urinary system
Abciximab may cause dysuria, hematuria, renal dysfunction, urinary frequency, urinary incontinence, urine retention , cystalgia and prostatitis.
The respiratory side effects include bronchitis, bronchospasm, crackles, dyspnea, pleural effusion, pneumonia, pulmonary edema, pulmonary embolism, wheezing, pleurisy, ronchi and rales.
Abciximab may cause wound cellulitis, bullous eruption at the injection site, pruritus, rash, and urticaria.
Myalgia , back pain and asthenia have been reported in patients receiving abciximab.
There are unusual side effects in the endocrine system and have included diabetes mellitus and hyperkalemia.
Administration of abciximab leads to development of human anti chimeric antibody (HACA) that are specific to murine epitope of Fab antibody fragment, this may cause potentially serious complications like severe thrombocytopenia, anaphylaxis or a diminished effect on readministration. However further studies are needed to verify these findings.