The following tetracycline has the potential to cause vestibular toxicity:

Correct Answer: C

Rationale: Step-by-step rationale: 1. Minocycline is known to cause vestibular toxicity due to its lipophilicity and ability to accumulate in inner ear structures. 2. Vestibular toxicity can manifest as dizziness, vertigo, and imbalance. 3. Doxycycline, oxytetracycline, and demeclocycline are less likely to cause vestibular toxicity. 4. Doxycycline is commonly used and well-tolerated, oxytetracycline has a different side effect profile, and demeclocycline is primarily associated with nephrotoxicity. Summary: Choice C (Minocycline) is correct due to its propensity for causing vestibular toxicity. Choices A, B, and D are incorrect as they are less likely to cause this specific adverse effect.

Correct Answer: A

Rationale: The correct answer is A: Griseofulvin. Griseofulvin is the drug of choice for ringworm infection because it specifically targets the fungus that causes ringworm. It works by inhibiting fungal cell division, leading to the destruction of the fungus. Amphotericin B is an antifungal medication used for systemic fungal infections, not for ringworm. Nystatin is used to treat fungal infections of the skin, mouth, and intestines, but it is not the first-line treatment for ringworm. Neomycin is an antibiotic used to treat bacterial infections, not fungal infections like ringworm. Therefore, Griseofulvin is the most appropriate choice for treating ringworm.

Correct Answer: C

Rationale: The correct answer is C: Primaquine. Primaquine is used for clinical curative treatment of malaria, particularly for the eradication of hypnozoites in Plasmodium vivax and Plasmodium ovale infections. It is not used as a prophylactic drug due to its potential side effects, such as hemolysis in individuals with G6PD deficiency. Choice A (Pyrimethamine + sulfadoxine) is a combination used for both treatment and prophylaxis. Choice B (Proguanil) is used for prophylaxis and treatment. Choice D (Mefloquine) is used for both prophylaxis and treatment of malaria.

Correct Answer: C

Rationale: The correct answer is C: Amantadine. Amantadine is an antiviral medication that is specifically effective against influenza A virus. It works by blocking the viral ion channel, preventing the virus from entering the host cell. This inhibits viral replication and helps reduce the severity and duration of symptoms. Choice A, Cidofovir, is used to treat certain DNA viruses but is not effective against influenza A. Choice B, Famciclovir, is used to treat herpes viruses, not influenza A. Choice D, Ribavirin, is an antiviral medication used for respiratory syncytial virus and hepatitis C, but not as effective against influenza A. Therefore, the most appropriate choice in this scenario is Amantadine due to its specific activity against influenza A virus.

Correct Answer: D

Rationale: Rationale for choice D: Retroviral protease inhibitors, such as lopinavir and ritonavir, are correct because they are more active in inhibiting HIV replication than zidovudine (B) and they inhibit CYP 3A4 and interact with many other drugs (C). Explanation for why other choices are incorrect: A: Retroviral protease inhibitors do not act at an early step in HIV replication; they act by blocking the protease enzyme necessary for viral maturation. B: Zidovudine is a nucleoside reverse transcriptase inhibitor, not a protease inhibitor, so retroviral protease inhibitors are more potent against HIV. C: While retroviral protease inhibitors do inhibit CYP 3A4 and interact with other drugs, this statement alone does not capture the complete picture of their mechanism of action or potency compared to zidovudine.