A 50-year-old male with hyperlipidemia is prescribed rosuvastatin. Rosuvastatin works by:

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: 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.

Correct Answer: C

Rationale: The correct answer is C because gabapentin binds to calcium channels in the central nervous system. This action reduces the release of excitatory neurotransmitters, such as glutamate, which helps in reducing pain signals sent to the brain. Option A is incorrect as gabapentin does not directly affect serotonin levels. Option B is incorrect as gabapentin does not inhibit norepinephrine reuptake. Option D is incorrect as gabapentin does not increase dopamine release. Therefore, the correct mechanism of action for gabapentin is binding to calcium channels to modulate pain signaling.

Correct Answer: B

Rationale: Correct Answer: B - Inhibiting the production of clotting factors by the liver Rationale: 1. Warfarin is a vitamin K antagonist that inhibits the production of vitamin K-dependent clotting factors (Factors II, VII, IX, X) by the liver. 2. By reducing the production of these clotting factors, warfarin helps prevent blood clots in patients with conditions like atrial fibrillation. 3. Thrombin is a key enzyme in the blood clotting process, but warfarin does not directly inhibit its action. 4. Blocking platelet aggregation is the mechanism of action for antiplatelet drugs like aspirin, not warfarin. 5. Inhibiting fibrinogen activation is not a mechanism of action for warfarin, as it primarily targets the production of clotting factors.