indication

For use in the treatment of excessive postoperative bleeding.

pharmacology

Aminocaproic acid works as an antifibrinolytic. It is a derivative of the amino acid lysine. The fibrinolysis-inhibitory effects of aminocaproic acid appear to be exerted principally via inhibition of plasminogen activators and to a lesser degree through antiplasmin activity. Aminocaproic acid may be a possible prophylactic for vascular disease, as it may prevent formation of lipoprotein (a), a risk factor for vascular disease.

mechanism of action

Aminocaproic acid binds reversibly to the kringle domain of plasminogen and blocks the binding of plasminogen to fibrin and its activation to plasmin. With NO activation of plasmin, there is a reduction in fibrinolysis. This consequently will reduce the amount of bleeding post surgery. Elevated plasma levels of lipoprotein(a) have been shown to increase the risk of vascular disease. Lipoprotein 9a)a has two components, apolipoprotein B-100, linked to apolipoprotein (a). Aminocaproic acid may change the conformation of apoliprotein (a), changing its binding properties and potentially preventing the formation of lipoprotein (a).

toxicity

A few cases of acute overdosage with intravenous administration have been reported. The effects have ranged from no reaction to transient hypotension to severe acute renal failure leading to death. The intravenous and oral LD₅₀ were 3.0 and 12.0 g/kg respectively in the mouse and 3.2 and 16.4 g/kg respectively in the rat. An intravenous infusion dose of 2.3 g/kg was lethal in the dog.

biotransformation

Sixty-five percent of the dose is recovered in the urine as unchanged drug and 11% of the dose appears as the metabolite adipic acid.

absorption

Absorbed rapidly following oral administration. In adults, oral absorption appears to be a zero-order process with an absorption rate of 5.2 g/hr. The mean lag time in absorption is 10 minutes. After a single oral dose of 5 g, absorption was complete (F=1).

half life

The terminal elimination half-life is approximately 2 hours.

route of elimination

Renal excretion is the primary route of elimination, whether aminocaproic acid is administered orally or intravenously.