The following drug may cure typhoid fever, but does not prevent development of carrier state:

Correct Answer: D

Rationale: Step-by-step rationale: 1. Chloramphenicol is effective in curing typhoid fever by targeting the bacteria causing the infection. 2. However, chloramphenicol does not effectively eradicate the bacteria from the carrier state. 3. Ceftriaxone, ciprofloxacin, and cotrimoxazole are also effective in treating typhoid fever but do not specifically target the carrier state. 4. Therefore, the correct answer is D, Chloramphenicol, as it cures typhoid fever but does not prevent the carrier state.

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.

Correct Answer: D

Rationale: The correct answer is D because both Lamivudine and Human interferon α are commonly used to treat chronic hepatitis B. Lamivudine is a nucleoside analog reverse transcriptase inhibitor that helps inhibit viral replication. Human interferon α is a type of immunomodulatory drug that boosts the immune system to fight the virus. Amantadine (choice C) is not typically used for treating hepatitis B, making it incorrect. Therefore, the combination of Lamivudine and Human interferon α (choice D) is the most appropriate treatment option for chronic hepatitis B.