A 65-year-old female with chronic asthma is prescribed montelukast. Montelukast works by:

Correct Answer: A

Rationale: The correct answer is A: Blocking leukotriene receptors in the lungs. Montelukast is a leukotriene receptor antagonist, which works by blocking the action of leukotrienes, inflammatory mediators that cause bronchoconstriction and inflammation in asthma. By blocking leukotriene receptors, montelukast helps to reduce bronchoconstriction and inflammation in the lungs, thereby improving asthma symptoms. B: Relaxing bronchial smooth muscle by stimulating beta-2 adrenergic receptors is incorrect because montelukast does not directly stimulate beta-2 adrenergic receptors. C: Inhibiting the release of histamine from mast cells is incorrect because montelukast does not inhibit histamine release; it specifically targets leukotriene receptors. D: Increasing acetylcholine release in the lungs is incorrect because montelukast does not affect acetylcholine release.

Correct Answer: B

Rationale: The correct answer is B: Inhibiting glucagon release from the pancreas. Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist, which stimulates insulin secretion and inhibits glucagon release from the pancreas. By inhibiting glucagon release, liraglutide helps lower blood sugar levels in diabetic patients. Choices A, C, and D are incorrect because liraglutide does not directly increase insulin secretion, improve insulin sensitivity in peripheral tissues, or inhibit the absorption of glucose in the intestines.

Correct Answer: B

Rationale: Metformin is the correct answer as it works by increasing insulin sensitivity in type 2 diabetes. It does this by decreasing glucose production in the liver and improving insulin utilization in peripheral tissues. Insulin (A) is not used to increase insulin sensitivity but to directly lower blood sugar levels. Sulfonylureas (C) and DPP-4 inhibitors (D) work by stimulating insulin release and inhibiting its breakdown respectively, not by increasing insulin sensitivity.

Correct Answer: A

Rationale: The correct answer is A: Inhibiting the reabsorption of sodium in the kidneys. Hydrochlorothiazide is a thiazide diuretic that acts on the distal convoluted tubule of the nephron to inhibit the sodium-chloride symporter, leading to increased excretion of sodium and water. This mechanism results in decreased blood volume and subsequently lowers blood pressure, making it an effective treatment for hypertension. Option B is incorrect as hydrochlorothiazide does not block calcium channels. Option C is incorrect as hydrochlorothiazide actually increases the excretion of sodium and water, not potassium. Option D is incorrect as hydrochlorothiazide does not directly inhibit aldosterone secretion.

Correct Answer: A

Rationale: The correct answer is A: Blocking muscarinic receptors in the airways. Ipratropium is an anticholinergic medication that works by blocking muscarinic receptors in the airways, leading to bronchodilation. This blocks the action of acetylcholine, which normally causes bronchoconstriction in asthma. Option B, stimulating beta-2 adrenergic receptors, is incorrect because ipratropium does not directly target beta-2 receptors. Option C, inhibiting histamine release, is incorrect as ipratropium does not affect histamine release. Option D, increasing acetylcholine release, is incorrect as ipratropium actually blocks the action of acetylcholine.