A 60-year-old male with hyperlipidemia is prescribed fenofibrate. Fenofibrate works by:

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: A

Rationale: The correct answer is A: Hair loss. Chemotherapy drugs target fast-growing cells, including hair follicles, leading to hair loss. This is a well-known side effect of chemotherapy. Increased appetite (B) is not a common side effect; in fact, many patients experience loss of appetite. Dehydration (C) can occur due to other reasons like nausea and vomiting, not directly from chemotherapy. Drowsiness (D) is more associated with certain medications or the cancer itself, not a direct side effect of chemotherapy.

Correct Answer: A

Rationale: The correct answer is A: Levothyroxine. Levothyroxine is a synthetic form of the thyroid hormone T4, used to treat hypothyroidism by supplementing the deficient thyroid hormone levels in the body. It helps regulate metabolism, energy levels, and overall bodily functions. Methimazole (B) is used to treat hyperthyroidism by reducing the production of thyroid hormones. Fluoxetine (C) is an antidepressant, not used for thyroid conditions. Lithium (D) is used for bipolar disorder, not for hypothyroidism. In summary, Levothyroxine is the correct choice as it directly replaces the deficient thyroid hormone, while the other options are not indicated for treating hypothyroidism.

Correct Answer: B

Rationale: The correct answer is B: Inhibiting HMG-CoA reductase in the liver. Rosuvastatin is a statin medication that works by inhibiting the enzyme HMG-CoA reductase, which plays a key role in the liver's production of cholesterol. By inhibiting this enzyme, rosuvastatin reduces the synthesis of cholesterol in the liver, leading to decreased levels of LDL cholesterol in the bloodstream. This mechanism helps lower the risk of cardiovascular events in patients with hyperlipidemia. Choice A is incorrect because rosuvastatin does not directly inhibit the absorption of cholesterol in the intestines. Choice C is incorrect as rosuvastatin primarily lowers LDL cholesterol levels and has minimal impact on increasing HDL cholesterol levels. Choice D is incorrect as rosuvastatin does not directly increase the excretion of cholesterol in the bile.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Atorvastatin, simvastatin, and lovastatin are all statin medications that lower cholesterol by inhibiting the HMG-CoA reductase enzyme. This enzyme is crucial in the production of cholesterol in the liver. By inhibiting this enzyme, statins help reduce the amount of cholesterol synthesized in the body, leading to lower overall cholesterol levels. Therefore, all three medications listed are effective in lowering cholesterol levels. The other choices (A, B, C) are incorrect as they do not fully address the question and fail to acknowledge that all three medications listed are part of the same drug class with the same mechanism of action.