Which of the following sedative-hypnotic drugs does not potentiate the CNS depressant effects of ethanol phenothiazines or tricyclic antidepressants?

Correct Answer: A

Rationale: Rationale: 1. Buspirone is a non-benzodiazepine anxiolytic that acts on serotonin receptors, not GABA receptors like other sedative-hypnotic drugs. 2. Since it does not target GABA receptors, it does not potentiate CNS depressant effects of ethanol, phenothiazines, or tricyclic antidepressants. 3. This makes it the only drug in the list that does not interact with these substances, making it the correct answer. Summary: - Phenobarbital, Diazepam, and Chloralhydrate are sedative-hypnotic drugs that potentiate CNS depressant effects of ethanol and other drugs due to their action on GABA receptors. - Buspirone, on the other hand, does not potentiate these effects as it acts on serotonin receptors, not GABA receptors.

Correct Answer: B

Rationale: The correct answer is B: Sucralfate. Sucralfate forms a physical barrier by binding to the ulcer site, protecting it from stomach acid and pepsin. Ranitidine (A) and Omeprazole (C) are both acid-reducing drugs that work by inhibiting acid production. Pirenzepine (D) is a muscarinic receptor antagonist that decreases acid secretion but does not form a physical barrier. Therefore, Sucralfate is the correct choice for forming a physical barrier to HCl and pepsin.

Correct Answer: B

Rationale: The correct answer is B because aspirin inhibits cyclooxygenase (COX) enzyme, which is responsible for thromboxane synthesis. Thromboxane promotes platelet aggregation and vasoconstriction. By inhibiting thromboxane synthesis, aspirin reduces platelet aggregation, making it an effective antiplatelet agent. Choice A is incorrect because plasminogen is not involved in the mechanism of aspirin action. Choice C is incorrect because it describes the mechanism of heparin, not aspirin. Choice D is incorrect because inhibiting the glycoprotein IIb/IIIa complex is the mechanism of action of drugs like abciximab, not aspirin.

Correct Answer: B

Rationale: Verapamil is a calcium channel blocker that primarily acts on the heart and has limited vasodilatory effects. Nifedipine, on the other hand, is a potent vasodilator that primarily acts on blood vessels. Therefore, the statement that verapamil is a more potent vasodilator than nifedipine is FALSE. Other choices (A, C, D) are incorrect because verapamil is not a more potent vasodilator compared to nifedipine.

Correct Answer: C

Rationale: The correct answer is C because angiotensin II is more potent than angiotensin I. Angiotensin II is a peptide hormone that stimulates aldosterone secretion and acts as a potent vasoconstrictor. Angiotensin I is an inactive precursor that is converted to angiotensin II by the enzyme ACE. Angiotensin II is more biologically active and has stronger effects on vasoconstriction and aldosterone release compared to angiotensin I. Therefore, statement C is false as angiotensin II is more potent than angiotensin I.