Which of the following statements refers to 1,25-dihydroxyvitamin D3 (calcitriol):

Correct Answer: A

Rationale: Rationale: A: Correct. Calcitriol regulates calcium and phosphate levels, leading to potential ectopic calcification. Monitoring is crucial. B: Incorrect. Calcitriol does undergo enterohepatic circulation. C: Incorrect. Calcitriol is not toxic to osteoclasts; it has a role in bone health. D: Incorrect. Calcitriol has a complex relationship with bioavailability, affected by several factors.

Correct Answer: C

Rationale: The correct answer is C: Imipenem, as it belongs to the carbapenem class of antibiotics. Carbapenems are broad-spectrum antibiotics effective against a wide range of bacteria, including some that are resistant to other antibiotics. Imipenem is specifically known for its activity against gram-positive and gram-negative bacteria. A: Aztreonam is a monobactam antibiotic, not a carbapenem. B: Amoxicillin is a penicillin antibiotic, not a carbapenem. D: Clarithromycin is a macrolide antibiotic, not a carbapenem. In summary, only Imipenem (Choice C) is a carbapenem antibiotic, making it the correct choice for this question.

Correct Answer: B

Rationale: The correct answer is B: Isoniazid. It is a first-line antimycobacterial drug used for treating tuberculosis. It targets the mycobacterial cell wall synthesis, specifically inhibiting mycolic acid production. This makes it effective against Mycobacterium tuberculosis. PAS (A) is a second-line drug with a different mechanism. Kanamycin (C) is also a second-line drug used for drug-resistant TB. Pyrazinamide (D) is a first-line drug, but it works by a different mechanism compared to isoniazid.

Correct Answer: D

Rationale: The correct answer is D: Niclosamide. Niclosamide is a salicylamide derivative used to treat tapeworm infections. This drug works by disrupting the mitochondrial function of parasites. Explanation: 1. Praziquantel (A) is used to treat schistosomiasis, not a salicylamide derivative. 2. Piperazine (B) is used to treat roundworm infections, not a salicylamide derivative. 3. Mebendazole (C) is an anthelmintic used to treat various worm infections, not a salicylamide derivative. In summary, Niclosamide is the correct choice as it is a salicylamide derivative specifically used for tapeworm infections, while the other options are used for different types of worm infections.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Cytoprotectors help protect healthy cells from damage caused by cancer treatment. Bone marrow growth factors aid in stimulating the production of blood cells, which can be suppressed during cancer treatment. Antimetastatic agents help prevent the spread of cancer to other parts of the body. Therefore, all these groups of drugs are used as subsidiary medicines in cancer treatment to support the primary treatment and manage side effects. Choices A, B, and C are incorrect individually because each group plays a specific role in supporting cancer treatment, making the combination of all three necessary for comprehensive care.