Jawaharlal Nehru Technological University Hyderabad B.Pharmacy III Year PHARMACOLOGY-II Previous Question Paper (March-2021 - R17)

Digoxin is a cardiac glycoside that exerts its positive inotropic effect primarily by inhibiting the Na+/K+-ATPase pump on the myocardial cell membrane. This inhibition leads to an increase in intracellular sodium concentration, which subsequently reduces the activity of the Na+/Ca2+ exchanger, causing an accumulation of intracellular calcium. This increased calcium availability enhances the force of myocardial contraction.

The common adverse drug reactions (ADRs) of Digoxin include gastrointestinal disturbances (anorexia, nausea, vomiting, and diarrhea), cardiac arrhythmias (such as bradycardia, AV block, and ventricular extrasystoles), and neurological symptoms like visual disturbances (xanthopsia or yellow-green halos around objects), fatigue, and confusion.

Anti-anginal drugs are classified as follows: 1) Organic Nitrates (e.g., Nitroglycerin, Isosorbide dinitrate), 2) Beta-adrenergic blockers (e.g., Propranolol, Atenolol), 3) Calcium channel blockers (e.g., Verapamil, Amlodipine), and 4) Potassium channel openers (e.g., Nicorandil).

Anti-hypertensive drugs act through various mechanisms: Diuretics (e.g., Thiazides) reduce blood volume by inhibiting sodium reabsorption; ACE inhibitors (e.g., Enalapril) block the conversion of Angiotensin I to Angiotensin II, a potent vasoconstrictor; Calcium channel blockers inhibit calcium influx into vascular smooth muscle, causing vasodilation; and Beta-blockers reduce cardiac output and inhibit renin release. ADRs vary by class: ACE inhibitors often cause a dry cough and hyperkalemia; diuretics may lead to hypokalemia and dehydration; calcium channel blockers can cause peripheral edema, flushing, and constipation; and beta-blockers may cause bradycardia, fatigue, and bronchospasm in susceptible individuals.