Cardiovascular Drugs Quiz for Cardiac Pharmacology Review

In heart failure with hypertension, ACE inhibitors reduce afterload and inhibit RAAS, decreasing mortality. Loop diuretics reduce pulmonary congestion by promoting sodium and water excretion, lowering preload. Together they optimize hemodynamics. Antiplatelets and anticoagulants do not directly manage volume or remodeling. Vasodilators alone are insufficient without neurohormonal blockade. Therefore, ACE inhibitors combined with diuretics address preload, afterload, and maladaptive RAAS activation effectively in these patients.

ACE inhibitors dilate the efferent arteriole, reducing intraglomerular pressure and preventing hyperfiltration injury in diabetic nephropathy. By blocking angiotensin II formation, they decrease vasoconstriction and proteinuria progression. Beta blockers do not provide direct renal protection. NSAIDs worsen renal perfusion by inhibiting prostaglandins. Antihistamines have no antihypertensive role. Therefore, ACE inhibitors both control blood pressure and protect kidney function in diabetic patients effectively.

Labetalol blocks beta and alpha receptors, lowering blood pressure safely in pregnancy without affecting fetal renal development. ACE inhibitors and ARBs interfere with fetal kidney formation and are contraindicated. Metoprolol lacks sufficient alpha blockade. Losartan is teratogenic. Labetalol reduces systemic vascular resistance while maintaining uteroplacental perfusion, making it a preferred antihypertensive in pregnant patients with elevated blood pressure.

Chronic nitrate exposure causes tolerance through continuous nitric oxide-mediated vasodilation. During weekends, absence of exposure reverses tolerance. Re-exposure on Monday produces exaggerated cerebral vasodilation via increased cGMP in vascular smooth muscle, triggering headache. This phenomenon is known as Monday disease. It reflects rapid tachyphylaxis and loss of vascular adaptation rather than infection or migraine pathology.

HMG-CoA reductase converts HMG-CoA to mevalonate, the committed and rate-limiting step in cholesterol synthesis. Insulin upregulates this enzyme, increasing cholesterol production. Statins competitively inhibit it, reducing LDL levels and cardiovascular risk. Lipoprotein lipase functions in triglyceride metabolism, not synthesis. ACAT esterifies cholesterol intracellularly. Thus, HMG-CoA reductase governs cholesterol biosynthetic flux and is the primary pharmacologic target.

Sublingual nitroglycerin bypasses hepatic first-pass metabolism because venous drainage from oral mucosa enters systemic circulation directly. Oral administration leads to extensive hepatic degradation, reducing bioavailability. Sublingual delivery provides rapid onset for angina relief. Faster intestinal absorption is irrelevant because hepatic metabolism still occurs. Therefore, avoiding portal circulation ensures higher plasma drug concentration and quicker therapeutic action.

Quinidine has antimuscarinic effects that enhance AV nodal conduction. In atrial flutter with 2:1 block, slowing atrial rate can permit 1:1 conduction through the AV node, increasing ventricular rate. Without AV nodal blockade, ventricular response may accelerate. This reflects altered conduction ratios rather than new arrhythmia formation. Hence, pre-treatment with AV nodal blockers prevents excessive ventricular rate transmission.

ACE normally degrades bradykinin. Inhibition increases bradykinin accumulation, stimulating prostaglandin production and vascular permeability. Elevated bradykinin triggers persistent dry cough and may cause angioedema due to enhanced vasodilation and capillary leakage. ARBs do not increase bradykinin significantly. Histamine is not the mechanism. Therefore, bradykinin accumulation explains these characteristic adverse effects of ACE inhibitors.

Loop diuretics partly rely on renal prostaglandins to maintain afferent arteriolar dilation and natriuresis. NSAIDs inhibit cyclooxygenase, reducing prostaglandin synthesis. This decreases renal blood flow and diuretic efficacy, promoting sodium and water retention. In heart failure patients, fluid accumulation precipitates pulmonary edema and weight gain. Thus, NSAIDs antagonize diuretic action and worsen heart failure symptoms.

Most loop diuretics contain sulfonamide groups, posing allergy risk in susceptible individuals. Ethacrynic acid lacks a sulfa moiety while providing similar inhibition of the Na-K-2Cl transporter in the thick ascending limb. Therefore, it is preferred in patients with sulfonamide hypersensitivity. Hydrochlorothiazide and furosemide contain sulfa structures and may provoke allergic reactions.

Digoxin competes with potassium for binding at Na-K ATPase. Hypokalemia increases digoxin binding affinity, enhancing its inhibitory effect and raising toxicity risk, including arrhythmias. Loop and thiazide diuretics cause potassium loss, predisposing patients. Hyperkalemia reduces binding. Thus, maintaining normal potassium levels is critical to prevent exaggerated digoxin pharmacologic effects.

Beta blockers inhibit B1 receptors in the AV node, slowing conduction velocity and increasing refractory period. This prolongs the PR interval on electrocardiogram. They also block B1 receptors in juxtaglomerular cells, decreasing renin release and RAAS activation. Reduced renin lowers sodium retention and blood pressure. Increased conduction would shorten PR, which does not occur.

Pulmonary fibrosis causes restrictive lung disease with proportional reductions in FEV and FVC. Because both values decline similarly, the FEV/FVC ratio remains normal or slightly increased. Obstructive diseases reduce FEV disproportionately, lowering the ratio. Amiodarone toxicity leads to restrictive patterns; therefore, preserved ratio distinguishes it from obstructive pathology.

Hyperthyroidism increases beta-adrenergic receptor density and sympathetic sensitivity, promoting atrial fibrillation. Propranolol blocks beta receptors, reducing heart rate and peripheral conversion of T4 to T3. Digoxin is less effective in high sympathetic states. Amiodarone contains iodine and may worsen thyroid dysfunction. Thus, beta blockade addresses both arrhythmia control and thyroid-mediated adrenergic excess.

Hydralazine directly dilates arterioles, lowering systemic vascular resistance and blood pressure. Baroreceptor activation triggers reflex sympathetic stimulation, causing tachycardia. Simultaneously, RAAS activation promotes sodium and water retention. These compensatory responses counteract blood pressure reduction. Therefore, beta blockers and diuretics are often co-administered to prevent reflex tachycardia and fluid accumulation.