Anticoagulation excessive

When the temperature of the plasma reaches about 5° to 8°C, the calculated quantity of calcium chloride solution is added in amount which is from 0.2 to 0.3% in excess of that needed to react with and precipitate the anticoagulant. The temperature of the plasma is allowed to rise to about 24°C. At 18° to 24°C strands of fibrin begin to appear and the... 

Patients receiving oral anticoagulants need to avoid eating excessive amounts ot food containing vitamin K. Otherwise, the anticoagulant will not be effective. Be sure your patient knows what foods contain vitamin K. Include the following list in your teaching plan ... 

Weak anticoagulant when excessively dosed (decreases factor VII levels). May have an antiplatelet effect... 

Excessive vitamin C doses Diabetics, patients prone to recurrent renal calculi, those undergoing stool occult blood tests and those on sodium restricted diets or anticoagulant therapy should not take excessive doses of vitamin C over an extended time period. 

Inject subcutaneously or IM when possible. In older children and adults, inject IM in the upper outer quadrant of the buttocks. In infants and young children, the anterolateral aspect of the thigh or the deltoid region is preferred. When IV administration is unavoidable, inject very slowly, not exceeding 1 mg/min. Anticoagulant-induced prothrombin deficiency in adults 2.5 to 10 mg or up to 25 mg (rarely, 50 mg) initially. Determine subsequent doses by prothrombin time (PT) response or clinical condition. If in 6 to 8 hours after parenteral administration (or 12 to 48 hours after oral administration), the PT has not been shortened satisfactorily, repeat dose. If shock or excessive blood loss occurs, transfusion of blood or fresh frozen plasma may be required. 

Coumarins are competitive inhibitors of vitamin K, which is required for the formation in the liver of the amino acid, gamma-carboxyglutamic acid. This is necessary for the synthesis of prothrombin and factors VII, IX and X (Figure 17.1). After starting treatment the anticoagulant effect is delayed until the concentration of normal coagulation factors falls (36-72 h). The effects can be reversed by vitamin K (slow maximum effect only after 3-6 h) or by whole blood or plasma (fast). Gut bacteria synthesise vitamin K and thus are an important source of this vitamin. Consequently, antibiotics can cause excessive prolongation of the prothrombin time in patients otherwise adequately controlled on warfarin. 

Excessive anticoagulant action of heparin is treated by discontinuance of the drug. If bleeding occurs, administration of a specific antagonist such as protamine sulfate is indicated. Protamine is a highly basic peptide that combines with heparin as an ion pair to form a stable complex devoid of anticoagulant activity. For every 100 units of heparin remaining in the... 

The physiological role of vitamin K is in blood clotting and is essential for the synthesis of at least four of the proteins (including prothrombin) involved in this process. Vitamin K also plays a role in the synthesis of a protein (osteocalcin) in bone. Vitamin K deficiency is rare but can result from impaired absorption of fat. Vitamin K levels in the body are also reduced if the intestinal flora is killed (e.g. by antibiotics). Vitamin K toxicity is rare but can be caused by excessive intake of vitamin K supplements. Symptoms include erythrocyte haemolysis, jaundice, brain damage and reduced effectiveness of anticoagulants. 

Warfarin (Fig. 10-22c) is a synthetic compound that inhibits the formation of active prothrombin. It is particularly poisonous to rats, causing death by internal bleeding. Ironically, this potent rodenticide is also an invaluable anticoagulant drug for treating humans at risk for excessive blood clotting, such as surgical patients and those with coronary thrombosis. ... 

Two patients taking oral anticoagulants developed excessive anticoagulant activity shortly after they had begun to take a course of tibolone (7). This seems to be a specific interaction, apparently similar to that seen with more potent estrogens, and the dose of anticoagulant may need to be reduced when tibolone is taken the problem did not seem to arise consistently with other hormone replacement formulations. 

---