Cardiovascular Drugs Our Patients Take
Course Number: 581
Course Contents
Drugs that Affect Hemostasis
A well-regulated hemodynamic system keeps blood fluid and clot-free in normal vessels and forms a localized clot rapidly in injured vessels.9 The first step in the formation of a localized clot at the site of vessel injury is vasoconstriction. This is followed by platelet aggregation and the formation of a primary hemostatic plug. Secondary hemostasis, also known as the coagulation cascade, leads to the formation of a stable, permanent clot. An abnormal extension of hemostasis is thrombosis.9
Thrombosis is characterized by the uncontrolled enlargement of clots that occlude blood vessels as a result of (1) injury of the endothelium associated with hyperlipidemia and hypertension; (2) abnormal blood flow, i.e. turbulence or stasis associated with atherosclerosis, arrhythmias, valvular problems, and heart failure, and (3) genetic or acquired hypercoagulability.9 Drugs in the top 300 that affect hemostasis (Table 5) fall into two major categories: antiplatelet agents and anticoagulants.2,9,10
Table 5. Drugs that Affect Hemostasis and Thrombosis.2,9,10
Drugs* | Mechanisms of Action | Common Indications |
---|---|---|
Class IC antiarrhythmics
| Block voltage-gated Na+ channels in ventricular myocytes | Sustained ventricular tachycardia Paroxysmal supraventricular tachycardia Paroxysmal atrial fibrillation |
Cyclooxygenase inhibitors
| Inhibit platelet cyclooxygenase, thereby
| Prophylaxis against
|
ADP receptor pathway inhibitors
| Block platelet ADP receptors thereby
| Secondary prevention of atherosclerotic events in patients with recent MI, stroke, or peripheral vascular disease Acute coronary syndromes Prevention of stent thrombosis in combination with aspirin |
Traditional anticoagulants
| Inhibit hepatic peroxide reductase that catalyzes the regeneration of reduced vitamin K, which is required for the synthesis of biologically active coagulation factors II, VII, IX, and X | Prophylaxis and treatment
|
Selective Factor Xa inhibitors
| Competitively inhibit factor Xa by binding to the active side on the enzyme | Prevention
Prevention and treatment
|
Direct thrombin inhibitors
| Bind directly to thrombin and thereby inhibit secondary hemostasis | Prevention
Treatment
|