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Anticoagulant Rodenticide Toxicity (view source)
Revision as of 12:35, 23 August 2010
, 12:35, 23 August 2010→Description
during the coagulation process and thus cannot
during the coagulation process and thus cannot
actively participate in fibrin formation.
actively participate in fibrin formation.
Warfarin and similar compounds interfere with the regeneration of vitamin K from an intermediate formed during the action
of vitamin K as an essential co-factor in the production of several of the factors involved in the clotting cascade. This is by competitive
inhibition of the enzyme involved in the regenerative process and leads to a reduction in available vitamin K, thereby resulting
in defective blood clotting. Vitamin K dependent clotting factors are VII, IX, 11 and X so the intrinsic pathway (activated by blood
vessel injury), the extrinsic pathway (activated by tissue injury) and the final common pathway (with conversion of prothrombin
to thrombin, formation of fibrin and stabilisation of the platelets) is affected. However, the primary haemostatic response (formation
of platelet plug) is unaffected.
Increased blood vessel fragility also appears to be a result of coumarin toxicity and may account for bleeding at sites that are
not subject to external trauma.
Following absorption, coumarins are carried bound to plasma albumin. Therefore, effects are potentiated by drugs that are also
bound to albumin such as phenylbutazone, or conditions that result in low plasma albumin levels such as renal insufficiency.
==Signalment==
==Signalment==