Rare Coagulation Factor Deficiencies

Chapter 62 Rare Coagulation Factor Deficiencies

Adjuncts to Factor Replacement Therapy in Congenital Factor Deficiencies

The antifibrinolytic agents ε-amino caproic acid and tranexamic acid can be effective adjuncts to factor replacement when treating congenital or acquired bleeding disorders and may be useful alternatives to replacement therapy for mild bleeding or minor procedures. These drugs inhibit clot dissolution by blocking plasminogen activation and plasmin activity and are particularly valuable when bleeding involves tissues with high fibrinolytic activity such as the oral cavity. They are also useful for treating menorrhagia, limiting blood loss with surgery, controlling epistaxis, and reducing some types of gastrointestinal bleeding. A typical loading dose of ε-amino caproic acid is 50 to 100 mg/kg followed by 2 to 4 grams every 6 hours. If bleeding subsequently occurs, the dose can be increased to a maximum of 24 grams in 24 hours. ε-Amino caproic acid is available in oral and intravenous formulations. Identical dosing may be used for either preparation because of excellent bioavailability. For dental extraction in factor VIII or IX deficiency, many centers use a single 50% to 100% loading dose of clotting factor concentrate followed by seven days of ε-amino caproic acid as the sole prophylaxis, and it is reasonable to extrapolate this approach to patients with some of the rare bleeding disorders. Patients with factor XI deficiency do well with antifibrinolytic agents alone for tooth extractions. Dental procedures such as scaling or root canal can be performed safely using ε-amino caproic acid or tranexamic acid mouthwash prepared from the intravenous formulation three to four times daily with or without systemic antifibrinolytic therapy.

Prolonged therapy with antifibrinolytic agents must be undertaken with caution in patients who are not mobile, who have a history of thromboembolic events, or who have significant urogenital bleeding. These drugs interfere with urokinase-mediated fibrinolytic activity in the genitourinary tract and can cause renal outflow obstruction by thrombotic occlusion of the ureters. Concomitant use of antifibrinolytic agents with activated prothrombin complex concentrates or recombinant factor VIIa may result in a particularly high risk for thrombus formation. Patients may develop nausea or vertigo with high doses of ε-amino caproic doses, and rarely, rhabdomyolysis.

Jun 12, 2016 | Posted by in HEMATOLOGY | Comments Off on Rare Coagulation Factor Deficiencies
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