Which of the following drugs is used to treat high cholesterol by inhibiting the absorption of cholesterol in the small intestine?

Correct Answer: B

Rationale: The correct answer is B: Ezetimibe. Ezetimibe works by inhibiting the absorption of cholesterol in the small intestine, reducing the amount of cholesterol that enters the bloodstream. Atorvastatin and Simvastatin are statins that work by reducing the production of cholesterol in the liver. Fenofibrate is a fibrate drug that helps lower triglycerides, not specifically targeting cholesterol absorption in the small intestine. Therefore, the correct choice is B as it directly addresses the mechanism of inhibiting cholesterol absorption in the small intestine.

Correct Answer: A

Rationale: The correct answer is A because hydralazine works by relaxing vascular smooth muscle through a direct vasodilatory effect, leading to decreased systemic vascular resistance and afterload. This relaxation occurs by increasing nitric oxide production, which promotes vasodilation. This mechanism helps reduce the workload on the heart and improve cardiac output in patients with heart failure. Choice B is incorrect because hydralazine does not block beta-1 adrenergic receptors in the heart. Choice C is incorrect because hydralazine does not directly affect sodium excretion in the kidneys. Choice D is incorrect because hydralazine does not inhibit the conversion of angiotensin I to angiotensin II; that is the mechanism of action for ACE inhibitors.

Correct Answer: A

Rationale: The correct answer is A: Oxybutynin. Oxybutynin is an anticholinergic medication that helps relax the bladder muscles, reducing urinary urgency and frequency in overactive bladder. Oxybutynin blocks the action of acetylcholine, a neurotransmitter responsible for bladder contractions. This effect helps control symptoms of overactive bladder. Summary of incorrect choices: B: Loratadine is an antihistamine used for allergies and does not treat overactive bladder symptoms. C: Gabapentin is used for nerve pain and seizures, not specifically for overactive bladder. D: Cyclobenzaprine is a muscle relaxant used for muscle spasms, not for overactive bladder symptoms.

Correct Answer: A

Rationale: The correct answer is A: Phenytoin. Phenytoin is a sodium channel blocker that stabilizes the neuronal membrane by inhibiting repetitive firing of action potentials. This mechanism helps control seizures. Clonazepam (B) acts on GABA receptors, Valproate (C) increases GABA levels, and Gabapentin (D) modulates calcium channels - all different mechanisms not related to stabilizing neuronal membranes for seizure control.

Correct Answer: A

Rationale: The correct answer is A: Inhibiting osteoclast-mediated bone resorption. Raloxifene is a selective estrogen receptor modulator (SERM) that works by binding to estrogen receptors in bone tissue, inhibiting osteoclast activity, and reducing bone resorption. This helps to maintain bone density in patients with osteoporosis. Choices B and C are incorrect as raloxifene does not directly promote osteoblast activity or increase calcium absorption in the intestines. Choice D is also incorrect as raloxifene does not inhibit the synthesis of collagen.