JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD Pharm. D III Year PHARMACOLOGY – II Previous Question Paper (October - 2020 - R08)

Heparin acts by binding to antithrombin III, inducing a conformational change that accelerates the inactivation of thrombin (Factor IIa) and Factor Xa, thereby preventing fibrin formation. Its primary uses include the treatment and prophylaxis of deep vein thrombosis, pulmonary embolism, and unstable angina. Common adverse effects include bleeding (hemorrhage), heparin-induced thrombocytopenia (HIT), and osteoporosis with long-term use.

Alteplase (t-PA) is a fibrin-specific thrombolytic agent that converts plasminogen to plasmin directly at the site of a clot. Plasmin then degrades fibrin clots into soluble products. It is used in the treatment of acute myocardial infarction, acute ischemic stroke, and massive pulmonary embolism. Major adverse effects include systemic bleeding, intracranial hemorrhage, and allergic reactions.

Thiazide diuretics (e.g., hydrochlorothiazide) act by inhibiting the Na+/Cl- symporter in the distal convoluted tubule, leading to increased excretion of sodium, chloride, and water. They are primarily used in the management of hypertension, edema associated with heart failure, and nephrolithiasis due to hypercalciuria.

Potassium-sparing diuretics act through two mechanisms: Spironolactone acts as a competitive antagonist of aldosterone receptors in the collecting duct, while Amiloride and Triamterene directly block epithelial sodium channels (ENaC). Both mechanisms reduce sodium reabsorption and potassium excretion. They are used as adjuncts to other diuretics to prevent hypokalemia, in the treatment of hyperaldosteronism, and in heart failure to reduce mortality.