A patient receives 200 mg of a medication that has a half-life of 12 hours. How many mg of the drug would remain in the patient's body after 24 hours? _____

Correct Answer: A

Rationale: Rationale: After 24 hours, two half-lives of the medication have passed. Initially, 200 mg is halved to 100 mg after 12 hours (1st half-life), then halved again to 50 mg after another 12 hours (2nd half-life). Therefore, only 50 mg of the drug would remain after 24 hours. Summary of other choices: - B: 100 mg - Incorrect, this is the amount remaining after the first half-life, not after 24 hours. - C: 150 mg - Incorrect, this is not the correct calculation based on the drug's half-life. - D: 200 mg - Incorrect, the drug undergoes degradation over time due to its half-life, so the amount remaining after 24 hours is less than the initial dose of 200 mg.

Correct Answer: C

Rationale: The correct answer is C: Stratum corneum. The drug most likely acted on the outermost layer of the skin, the stratum corneum, as it is responsible for drug absorption and penetration. The other layers (A, B, D) are deeper layers of the skin and are not primarily involved in drug action. The stratum basale (A) is the innermost layer responsible for cell division, the stratum spinosum (B) provides strength and flexibility, and the pigment layer (D) contains melanocytes responsible for skin color. Therefore, the stratum corneum is the most likely site for drug action due to its role in drug absorption and penetration.

Correct Answer: B

Rationale: The correct answer is B: Albuterol. Albuterol is a bronchodilator that works by relaxing bronchial muscles, making it easier to breathe. It is commonly prescribed for the treatment of asthma to provide quick relief of symptoms. Prednisone (A) is a corticosteroid used for long-term control of asthma but does not directly relax bronchial muscles. Ipratropium (C) is an anticholinergic medication that helps open the airways but does not primarily target bronchial muscle relaxation. Methotrexate (D) is an immunosuppressant used for conditions like rheumatoid arthritis, not for asthma treatment.

Correct Answer: B

Rationale: The correct answer is B: Activating peroxisome proliferator-activated receptor alpha (PPAR-alpha). Fenofibrate is a fibrate medication that works by activating PPAR-alpha receptors. PPAR-alpha activation leads to increased expression of genes involved in lipid metabolism, resulting in decreased triglyceride levels and increased HDL cholesterol levels. This mechanism of action is specific to fenofibrate and other fibrates. Now, let's analyze why the other choices are incorrect: A: Inhibiting HMG-CoA reductase in the liver - This is the mechanism of action of statins, not fibrates like fenofibrate. C: Blocking calcium channels in the blood vessels - This is unrelated to the mechanism of action of fenofibrate and is more commonly associated with calcium channel blockers used in hypertension management. D: Increasing the absorption of cholesterol in the intestines - This is the mechanism of action of bile acid sequestrants, not fibrates like fenofibrate

Correct Answer: B

Rationale: The correct answer is B: Improving insulin sensitivity in peripheral tissues. Metformin works by decreasing insulin resistance in peripheral tissues, making them more responsive to insulin. This helps to lower blood glucose levels by improving glucose uptake and utilization. Choice A is incorrect because metformin does not directly increase insulin secretion from the pancreas. Choice C is incorrect as metformin does not inhibit glucose absorption in the intestines. Choice D is incorrect as metformin primarily reduces blood glucose levels by improving insulin sensitivity rather than increasing renal glucose excretion.