Which of the following is a common side effect of chemotherapy drugs?

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: 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.

Correct Answer: B

Rationale: The correct answer is B because celecoxib selectively inhibits COX-2 enzymes, which are responsible for producing prostaglandins involved in pain and inflammation. By targeting COX-2 specifically, celecoxib reduces pain and inflammation without affecting COX-1, which is important for maintaining gastrointestinal mucosa and platelet function. Therefore, choice A is incorrect as celecoxib does not inhibit both COX-1 and COX-2. Choices C and D are also incorrect as celecoxib does not increase prostaglandin synthesis or bind to opioid receptors.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Isoniazid is a first-line medication for tuberculosis due to its efficacy in killing the bacteria. 2. It works by inhibiting the synthesis of mycolic acids in the bacterial cell wall. 3. This disrupts the cell wall formation, leading to bacterial death. 4. Amoxicillin, ceftriaxone, and doxycycline are not typically used as first-line treatments for tuberculosis. Summary: Isoniazid is the correct choice for treating tuberculosis as it specifically targets the bacteria causing the infection. Amoxicillin, ceftriaxone, and doxycycline are not effective against tuberculosis bacteria.