Anticoagulant Drugs Quiz: Trivia! MCQ

Heparin is a drug that acts by accelerating the binding between antithrombin III and clotting factor proteases. It inhibits the formation of fibrin clots by preventing the conversion of fibrinogen to fibrin. This mechanism of action makes it an effective treatment for conditions such as pulmonary thromboembolism, where there is a clot formation in the blood vessels of the lungs. Warfarin, Aminocaproic acid, Alteplase, Clopidogrel, and Aspirin have different mechanisms of action and are not used for this purpose.

Clopidogrel is the correct answer because it acts by blocking platelet ADP receptors. By blocking these receptors, clopidogrel prevents platelets from aggregating and forming blood clots, which can help reduce the risk of further thromboembolic events, such as strokes. Warfarin, aminocaproic acid, alteplase, heparin, and aspirin do not have this specific mechanism of action.

Clopidogrel is a medication that is commonly used as an antiplatelet agent to prevent blood clot formation in patients with cardiovascular diseases. It works by irreversibly blocking the ADP receptors on platelets, preventing platelet activation and aggregation. This inhibitory effect on platelets reduces the risk of clot formation and helps in preventing complications associated with unstable angina. Therefore, the irreversible blockade of platelet ADP receptors is the molecular action that most likely mediates the therapeutic effect of clopidogrel in the patient's disease.

The patient's symptoms and signs, including black, tarry stools, subconjunctival hemorrhage, and bruises, are consistent with bleeding complications. Warfarin is an anticoagulant medication that works by inhibiting vitamin K-dependent clotting factors, leading to an increased risk of bleeding. The patient's history of prosthetic valve replacement and daily anticoagulant therapy further supports the likelihood that warfarin is the cause of her symptoms and signs.

Fibrinolytic drugs would be absolutely contraindicated for this patient because she is exhibiting symptoms of pericarditis, including substernal chest pain, friction rub, and fever. Fibrinolytic drugs are used to dissolve blood clots, but in the case of pericarditis, there is no clot formation. Therefore, fibrinolytic drugs would not be effective and could potentially worsen the patient's condition.

The correct answer is "Erythromycin-induced inhibition of warfarin metabolism". Erythromycin is known to inhibit the metabolism of warfarin, which is a blood thinner. This can lead to an increase in the levels of warfarin in the body, resulting in an increased risk of bleeding. The patient's symptoms of nose bleeding and red eyes are consistent with this increased risk of bleeding due to the interaction between erythromycin and warfarin.

Desmopressin is an appropriate therapy for the patient because it increases the plasma levels of factor VIII. Hemophilia A is a genetic disorder characterized by a deficiency or dysfunction of factor VIII, a blood clotting factor. Desmopressin stimulates the release of factor VIII from storage sites in the body, increasing its concentration in the blood. This can help prevent or control bleeding episodes in patients with hemophilia A.

Aminocaproic acid can act as an antidote to manage bleeding due to fibrinolytic therapy. Fibrinolytic therapy involves the use of drugs like alteplase to dissolve blood clots. However, these drugs can sometimes cause excessive bleeding. Aminocaproic acid works by inhibiting the breakdown of blood clots and preventing further bleeding. It helps to stabilize the clot and control bleeding in patients receiving fibrinolytic therapy.

The patient's symptoms and laboratory findings are consistent with heparin-induced thrombocytopenia (HIT), which is a known side effect of heparin therapy. HIT is characterized by a decrease in platelet count, as seen in this case, and can lead to the development of blood clots and tissue damage. The other drugs listed are not typically associated with these symptoms and signs.

Warfarin is a commonly used anticoagulant medication that works by inhibiting the synthesis of vitamin K-dependent clotting factors. This increases the risk of bleeding, including intracranial hemorrhage. In this case, the patient had an acute myocardial infarction and was found in a coma, indicating a severe condition. The CT scan showed intracranial hemorrhage in the left hemisphere, suggesting that the patient's condition was worsened by the use of warfarin, which increased the risk of bleeding in the brain. Aspirin, streptokinase, and ticlopidine are not typically associated with an increased risk of intracranial hemorrhage.

Abciximab,a glycoprotein IIb/IIIa receptor antagonist, is a platelet aggregation inhibitor mainly used during and after coronary artery procedures like angioplasty to prevent platelets from sticking together and causing thrombus (blood clot) formation within the coronary artery. It is a glycoprotein IIb/IIIa inhibitor. While Abciximab has a short plasma half-life, due to its strong affinity for its receptor on the platelets, it may occupy some receptors for weeks. In practice, platelet aggregation gradually returns to normal about 96 to 120 hours after discontinuation of the drug.

Fresh frozen plasma is most likely administered IV to the patient in this scenario. The patient's symptoms of red blood in stools and pink urine, along with the physical examination findings of pale appearance and low blood pressure, suggest significant bleeding. Warfarin, which the patient started two weeks ago, is an anticoagulant that can increase the risk of bleeding. Fresh frozen plasma contains clotting factors and can help replace the depleted factors in the patient, helping to control the bleeding.