Tick the drug with nonselective beta-adrenoblocking activity:

Correct Answer: B

Rationale: The correct answer is B: Propranolol. Propranolol is a nonselective beta-blocker, meaning it blocks both beta-1 and beta-2 adrenergic receptors. This leads to effects such as decreased heart rate, reduced blood pressure, and bronchoconstriction. Atenolol (choice A) and Metoprolol (choice C) are selective beta-1 blockers, primarily affecting the heart. Nebivolol (choice D) is a beta-1 blocker with vasodilatory properties. By blocking both beta-1 and beta-2 receptors, Propranolol has a wider range of effects compared to the other choices.

Correct Answer: D

Rationale: Step 1: Sulphonylureas are a class of drugs that stimulate insulin release. Step 2: They act by binding to the sulphonylurea receptor on beta islet cells of the pancreas. Step 3: This binding triggers a cascade of events leading to insulin release. Step 4: Insulin then helps lower blood glucose levels. Conclusion: Choice D is correct as it accurately describes the mechanism of action of sulphonylureas. Choices A, B, and C are incorrect as they do not reflect the primary mode of action of sulphonylureas.

Correct Answer: D

Rationale: The correct answer is D because glucocorticoids have a multi-faceted anti-inflammatory effect. 1. Glucocorticoids inhibit phospholipase A2, reducing prostaglandins and leukotrienes, which are pro-inflammatory mediators. 2. They also decrease macrophage migration to the site of inflammation, reducing inflammation. 3. Glucocorticoids decrease capillary permeability, which helps in reducing swelling and edema. Therefore, all of the above mechanisms contribute to the anti-inflammatory effect of glucocorticoids. Other choices are incorrect because they do not encompass all the key mechanisms involved in the anti-inflammatory effects of glucocorticoids.

Correct Answer: B

Rationale: Step 1: Histamine H1 antagonists are commonly used to treat allergic reactions by blocking histamine release. Step 2: Nausea and vomiting in pregnancy can be treated with H1 antagonists like doxylamine. Step 3: Sleep disorders are not typically treated with H1 antagonists, but rather with medications targeting other pathways. Step 4: Seizure states are not a common indication for H1 antagonists and have no direct relation to histamine pathways. Step 5: Therefore, choice B is the correct answer as it does not align with the typical indications for histamine H1 antagonists.

Correct Answer: B

Rationale: The correct answer is B because vitamin B1, also known as thiamine, is indeed an essential coenzyme for the oxidative decarboxylation of alpha-keto acids, including the conversion of pyruvate to acetyl coenzyme A in the citric acid cycle. This process is crucial for energy production in the form of ATP. Choice A is incorrect because vitamin B1 is not primarily an antioxidant but rather a coenzyme involved in energy metabolism. Choice C is incorrect because vitamin B1 is not required for the synthesis of prothrombin or clotting factors. Choice D is incorrect because flavoproteins, FMN, and FAD are associated with vitamin B2 (riboflavin), not vitamin B1.