Which of the following drugs for treatment of leprosy can cause hemolysis * especially in patients with G6PD deficiency?

Correct Answer: A

Rationale: Rationale: 1. Dapsone is a known cause of hemolysis in patients with G6PD deficiency due to oxidative stress. 2. Dapsone triggers the release of reactive oxygen species, leading to hemolysis in G6PD-deficient individuals. 3. Rifampicin and clofazimine do not have a direct association with hemolysis in G6PD deficiency. 4. Option D is incorrect as dapsone is a well-established drug associated with hemolysis in G6PD-deficient individuals.

Correct Answer: D

Rationale: The correct answer is D because Nevirapine is associated with an increased risk of severe hepatoxicity, especially within the first few weeks of treatment initiation. The recommended CD4 cell count thresholds for starting Nevirapine are lower in women compared to men to minimize this risk. In this case, women with CD4 cell counts >250 cells/mm3 and men with CD4 cell counts >450 cells/mm3 should not initiate Nevirapine due to the higher likelihood of developing hepatoxicity. A is incorrect because the CD4 cell count thresholds are too high for both women and men. B is incorrect as it sets the threshold for women too high. C is incorrect because the threshold for men is too high. Thus, D is the most appropriate choice based on the recommended guidelines to minimize the risk of severe hepatoxicity.

Correct Answer: D

Rationale: The correct answer is D: Procaine penicillin. Procaine penicillin is a long-acting penicillin formulation due to the addition of procaine, which slows down the release of penicillin into the bloodstream. This results in a prolonged duration of action compared to benzathine, sodium, and potassium penicillin. Benzathine penicillin is also long-acting but primarily used for prevention, not treatment. Sodium and potassium penicillin are not formulated for extended action, making them less suitable for long-term treatment. Therefore, D is the best choice for long-lasting penicillin therapy.

Correct Answer: B

Rationale: Correct Answer: B Rationale: 1. Metronidazole is a nitroimidazole antibiotic that requires activation by bacterial reductases to form nitro intermediates. 2. These activated intermediates bind DNA, leading to DNA strand breakage and inhibition of anaerobic bacterial replication. 3. This mechanism of action makes metronidazole effective against anaerobic bacteria. 4. Choice A is incorrect as metronidazole is not the first-line drug for amoebic dysentery or liver abscess - it is mainly used for anaerobic infections. 5. Choice C is incorrect as metronidazole is not the most effective drug for eradicating amoebic cysts in the colon; other drugs like tinidazole are preferred for that purpose. 6. Choice D is incomplete and does not provide any information related to metronidazole's mechanism of action.

Correct Answer: C

Rationale: The correct answer is C: Chloramphenicol. At lower concentrations, Chloramphenicol is primarily bacteriostatic, inhibiting bacterial protein synthesis. However, at higher concentrations, it can disrupt the bacterial ribosome, leading to bacterial cell death, making it bactericidal. Erythromycin (A) and Tetracycline (B) are primarily bacteriostatic by inhibiting protein synthesis. Ampicillin (D) interferes with bacterial cell wall synthesis but does not exhibit a concentration-dependent shift to bactericidal activity like Chloramphenicol.