The drug of choice for monilial diarrhea is:

Correct Answer: B

Rationale: Step-by-step rationale for why Nystatin is the correct choice for monilial diarrhea: 1. Nystatin is an antifungal medication specifically effective against Candida species causing monilial infections. 2. It works by binding to ergosterol in fungal cell membranes, disrupting membrane integrity and causing cell death. 3. Nystatin is not absorbed systemically, making it suitable for gastrointestinal infections. 4. Amphothericin B is reserved for severe systemic fungal infections due to its significant toxicity. Ketoconazole and Itraconazole are not typically used for gastrointestinal Candida infections, as they are more commonly used for systemic fungal infections.

Correct Answer: B

Rationale: The correct answer is B: Cefuroxime. Cefuroxime is a second-generation cephalosporin that has demonstrated in vitro activity against anaerobic gram-negative bacteria like Bacteroides fragilis. This is due to its broader spectrum of activity compared to other choices. A: Cefdinir is a third-generation cephalosporin with limited activity against anaerobic gram-negative bacteria. C: Cefazolin is a first-generation cephalosporin primarily effective against aerobic gram-positive bacteria. D: Cefepime is a fourth-generation cephalosporin with limited activity against anaerobic gram-negative bacteria.

Correct Answer: D

Rationale: The correct answer is D because both Ganciclovir and Foscarnet are active against cytomegalovirus (CMV). Ganciclovir works by inhibiting viral DNA polymerase, while Foscarnet inhibits viral DNA polymerase and reverse transcriptase. Acyclovir, on the other hand, is not effective against CMV as it primarily targets herpes simplex virus and varicella-zoster virus. Therefore, choices A and B are correct for CMV treatment, making option D the correct answer.

Correct Answer: B

Rationale: The correct answer is B: Lamivudine and zidovudine. Combivir is a combination therapy that contains these two drugs, which are commonly used together to treat HIV and AIDS. Lamivudine and zidovudine work synergistically to inhibit viral replication by targeting different stages of the HIV life cycle. Lamivudine is a nucleoside reverse transcriptase inhibitor (NRTI) that blocks the action of the enzyme reverse transcriptase, while zidovudine is also an NRTI that interferes with viral DNA synthesis. This combination helps reduce the viral load and improve the immune response in patients. Incorrect Choices: A: Lamivudine and stavudine - Stavudine is not part of the Combivir combination therapy. C: Abacavir and zidovudine - Abacavir is not part of the Combivir combination therapy. D: Abacavir and stavudine

Correct Answer: A

Rationale: Step-by-step rationale for choice A being correct: 1. Isoniazid can lead to pyridoxine deficiency. 2. Pyridoxine supplementation helps prevent neurotoxicity. 3. Thus, isoniazid therapy requires pyridoxine supplementation. Summary of why other choices are incorrect: B: Isoniazid does not effectively penetrate the BBB. C: Ocular complications of isoniazid are generally irreversible. D: Ototoxicity and nephrotoxicity are not common side effects of isoniazid.