Which of the following medications is used to treat seizures by stabilizing the neuronal membrane?

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: C

Rationale: The correct answer is C: Warfarin. Warfarin is an anticoagulant that helps prevent blood clots, reducing the risk of stroke in patients with atrial fibrillation. It is more effective than aspirin or clopidogrel in preventing stroke in this patient population. Heparin is not typically used for long-term stroke prevention in atrial fibrillation.

Correct Answer: B

Rationale: The correct answer is B because salmeterol is a long-acting beta-2 adrenergic agonist, which works by stimulating beta-2 adrenergic receptors on bronchial smooth muscle, leading to bronchodilation. This helps in relaxation of the airways and improved breathing in asthma patients. Option A is incorrect because salmeterol does not affect histamine release. Option C is incorrect as salmeterol does not inhibit leukotriene receptors. Option D is incorrect as salmeterol does not block acetylcholine receptors.

Correct Answer: B

Rationale: The correct answer is B: Osteoporosis. Corticosteroid therapy can lead to decreased bone density over time, resulting in osteoporosis. This occurs due to the suppression of bone formation and increased bone resorption. Hypotension (choice A) is not a common side effect of corticosteroid therapy; rather, it can cause fluid retention and hypertension. Tachycardia (choice C) is also not a typical side effect of corticosteroids; instead, they may cause bradycardia. Hyperkalemia (choice D) is not directly associated with corticosteroid therapy; in fact, corticosteroids can lead to hypokalemia due to potassium loss.

Correct Answer: B

Rationale: The correct answer is B: Improving insulin sensitivity in peripheral tissues. Metformin helps improve insulin sensitivity by increasing the uptake of glucose by muscle and fat cells, reducing glucose production in the liver, and decreasing insulin resistance. This leads to better control of blood glucose levels in individuals with type 2 diabetes. Choice A is incorrect because metformin does not directly increase insulin secretion from the pancreas. Choice C is incorrect because metformin does not inhibit glucose absorption in the intestines. Choice D is incorrect because although metformin may increase renal glucose excretion to some extent, its primary mechanism of action is improving insulin sensitivity in peripheral tissues.