Precautions for Amicar
General
AMICAR inhibits both the action of plasminogen activators and to a lesser degree, plasmin activity. The drug should NOT be administered without a definite diagnosis and/or laboratory finding indicative of hyperfibrinolysis (hyperplasminemia).1 Inhibition of fibrinolysis by aminocaproic acid may theoretically result in clotting or thrombosis. However, there is no definite evidence that administration of aminocaproic acid has been responsible for the few reported cases of intravascular clotting which followed this treatment. Rather, itappears that such intravascular clotting was most likely due to the patient's pre existing clinical condition, e.g.,the presence of DIC. It has been postulated that extravascular clots formed in vivo may not undergo spontaneouslysis as do normal clots.
Reports have appeared in the literature of an increased incidence of certain neurological deficits such ashydrocephalus, cerebral ischemia, or cerebral vasospasm associated with the use of antifibrinolytic agents in the treatment of subarachnoid hemorrhage (SAH). All of these events have also been described as part of the natural course of SAH, or as a consequence of diagnostic procedures such as angiography. Drug relatedness remains unclear.
Aminocaproic acid should not be administered with Factor IX Complex concentrates or Anti-Inhibitor Coagulant concentrates, as the risk of thrombosis may be increased.
Laboratory Tests
The use of AMICAR should be accompanied by tests designed to determine the amount of fibrinolysis present. There are presently available: (a) general tests such as those for the determination of the lysis of a clot of blood or plasma; and (b) more specific tests for the study of various phases of the fibrinolytic mechanisms. These latter tests include both semiquantitative and quantitative techniques for the determination of profibrinolysin, fibrinolysin, and anti fibrinolysin.
Drug Laboratory Test Interactions
Prolongation of the template bleeding time has been reported during continuous intravenous infusion of AMICAR at dosages exceeding 24 g/day. Platelet function studies in these patients have not demonstrated any significant platelet dysfunction. However, in vitro studies have shown that at high concentrations (7.4 mMol/Lor 0.97 mg/mL and greater) aminocaproic acid inhibits ADP and collagen-induced platelet aggregation, there lease of ATP and serotonin, and the binding of fibrinogen to the platelets in a concentration-response manner. Following a 10 g bolus of AMICAR, transient peak plasma concentrations of 4.6 mMol/L or 0.60 mg/mL have been obtained. The concentration of AMICAR necessary to maintain inhibition of fibrinolysis is 0.99 mMol/Lor 0.13 mg/mL. Administration of a 5 g bolus followed by 1 to 1.25 g/hr should achieve and sustain plasma levels of 0.13 mg/mL. Thus, concentrations which have been obtained in vivo clinically in patients with normal renal function are considerably lower than the in vitro concentrations found to induce abnormalities in platelet function tests. However, higher plasma concentrations of AMICAR may occur in patients with severe renal failure.
Carcinogenesis, Mutagenesis, Impairment Of Fertility
Long-term studies in animals to evaluate the carcinogenic potential of AMICAR and studies to evaluate its mutagenic potential have not been conducted. Dietary administration of an equivalent of the maximum human therapeutic dose of AMICAR to rats of both sexes impaired fertility as evidenced by decreased implantations, litter sizes and number of pups born.
Pregnancy
Pregnancy Category C
Animal reproduction studies have not been conducted with AMICAR. It is also not known whether AMICAR can cause fetal harm when administered to a pregnant woman or can affect reproduction capacity. AMICAR should be given to a pregnant woman only if clearly needed.
Nursing Mothers
It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when AMICAR is administered to a nursing woman.
Pediatric Use
Safety and effectiveness in pediatric patients have not been established.
REFERENCE
1. Stefanini M, Dameshek W: The Hemorrhagic Disorders, Ed. 2, New York, Grune and Stratton; 1962:510-514.