Action of the parathyroid hormone is:

Correct Answer: D

Rationale: The correct answer is D because the parathyroid hormone (PTH) has multiple functions in the body. A: PTH increases calcium and phosphate absorption in the intestine by stimulating the production of active vitamin D. B: PTH decreases calcium excretion and increases phosphate excretion in the kidneys, helping to maintain serum calcium levels. C: In bone, PTH increases calcium and phosphate resorption at high doses and may increase bone formation at low doses. Therefore, all of the above statements are true, making D the correct choice.

Correct Answer: A

Rationale: Acetazolamide inhibits carbonic anhydrase in the proximal convoluted tubule, leading to decreased bicarbonate reabsorption and subsequent diuresis. This mechanism occurs at the site of action for the drug, making choice A the correct answer. Choices B, C, and D are incorrect because acetazolamide does not act directly at these sites within the nephron.

Correct Answer: C

Rationale: The correct answer is C: Amphotericin B. Amphotericin B is an antifungal medication used for systemic and deep mycotic infections due to its broad spectrum and effectiveness. It works by binding to ergosterol in the fungal cell membrane, leading to cell membrane disruption. Co-trimoxazole (A) is an antibiotic used for bacterial infections. Griseofulvin (B) is used for superficial fungal infections like ringworm. Nitrofungin (D) is an antifungal medication used for topical treatment. Therefore, Amphotericin B is the most appropriate choice for systemic and deep mycotic infections.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Metronidazole is the drug of choice for trichomoniasis due to its efficacy against the parasite. 2. Metronidazole works by disrupting the DNA structure of the parasite, leading to its death. 3. Suramin is used for African sleeping sickness, not trichomoniasis. 4. Pyrimethamine is used for malaria, not trichomoniasis. 5. Tetracycline is used for bacterial infections, not trichomoniasis. Summary: Metronidazole is the correct choice for trichomoniasis treatment due to its specific mechanism of action against the parasite. Suramin, pyrimethamine, and tetracycline are used for different infections and are not effective for trichomoniasis.

Correct Answer: B

Rationale: Step-by-step rationale: 1. Indinavir is a protease inhibitor used to treat HIV. 2. Nephrolithiasis is a known side effect due to indinavir crystal formation in kidneys. 3. Nausea is a common gastrointestinal side effect. 4. Hepatotoxicity is a serious unwanted effect due to liver damage. 5. Hypotension, vomiting, dizziness (Option A) are not associated with indinavir. 6. Peripheral neuropathy, pancreatitis, hyperuricemia (Option C) are not typical side effects of indinavir. 7. Anemia, neutropenia, nausea (Option D) are not specific to indinavir. Summary: - Option B is correct as nephrolithiasis and hepatotoxicity are known side effects of indinavir. - Options A, C, and D are incorrect as they include side effects not typically associated with indinavir.