Limitation of buspirone is:

Correct Answer: B

Rationale: Buspirone has a slow onset of action due to its mechanism of action involving serotonin and dopamine receptors. This makes it unsuitable for acute anxiety or panic attacks. The slow onset allows for gradual anxiolytic effects over time. Other choices are incorrect because buspirone has a wide therapeutic index, minimal potential for physical dependence, and does not typically impair mentation or motor functions.

Correct Answer: A

Rationale: The correct answer is A: Misoprostol. Misoprostol is an analog of prostaglandin E1, as it shares similar pharmacological properties. Prostaglandin E1 helps protect the stomach lining and promotes healing of ulcers. Misoprostol, by mimicking prostaglandin E1, can be used to prevent and treat ulcers caused by NSAIDs. De-nol (B) and sucralfate (C) work differently by forming a protective barrier over ulcers. Omeprazole (D) is a proton pump inhibitor that reduces stomach acid production, not an analog of prostaglandin E1.

Correct Answer: A

Rationale: The correct answer is A: Low. Low doses of Aspirin are more effective in inhibiting Thromboxane A2 because they irreversibly inhibit cyclooxygenase-1 in platelets, which is necessary for Thromboxane A2 synthesis. High doses can lead to non-specific inhibition of COX-1 and COX-2, which may cause side effects. Choice B is incorrect because high doses can lead to non-specific inhibition. Choice C is incorrect because high doses are not more effective. Choice D is incorrect as low doses are effective.

Correct Answer: C

Rationale: The correct answer is C, both Nifedipine and Verapamil are contraindicated in patients with moderate to severe heart failure due to their negative inotropic effects. These drugs can worsen heart failure symptoms by further reducing cardiac output. Nifedipine and Verapamil are calcium channel blockers that can lead to decreased contractility of the heart muscle, exacerbating heart failure. Choice A (Nifedipine) and choice B (Verapamil) are incorrect because they can be harmful in patients with heart failure. Choice D (None of the above) is incorrect as both drugs should be avoided in this patient population.

Correct Answer: A

Rationale: The correct answer is A: Propranolol. Propranolol is a non-selective beta-blocker that can cause bronchoconstriction in patients with asthma due to its beta-blocking effects on beta-2 receptors in the lungs. This can worsen asthma symptoms and potentially lead to an asthma attack. Clonidine (B), Enalapril (C), and Nifedipine (D) do not have direct effects on bronchial smooth muscle and are not contraindicated in patients with bronchial asthma.