This drug is a pyrophosphate analog which inhibit DNA polymerase and * reverse transcriptase, is used only to treat associated cytomegalovirus infection in AIDS patient.

Correct Answer: D

Rationale: The correct answer is D: Foscarnet. Foscarnet is a pyrophosphate analog that inhibits both DNA polymerase and reverse transcriptase, making it effective against cytomegalovirus (CMV) infections in AIDS patients. Acyclovir (A) and Valacyclovir (B) are antiviral drugs used for herpes infections, not CMV. Amantadine (C) is an antiviral used for influenza, not CMV. Therefore, Foscarnet is the correct choice for treating CMV in AIDS patients.

Correct Answer: D

Rationale: The correct answer is D because using antibiotic combinations covering both gram positive and gram negative bacteria can disrupt the balance of normal flora in the body, leading to superinfections. This is due to the broad spectrum of activity of these antibiotics, which can kill off a wider range of bacteria, including the beneficial ones. Choice A is incorrect because narrow spectrum antibiotics target specific types of bacteria, reducing the likelihood of disrupting the normal flora and causing superinfections. Choice B is incorrect because longer courses of antibiotics increase the risk of superinfections as they continue to disrupt the normal flora over a longer period. Choice C is incorrect because antibiotics that are completely absorbed from the small intestines do not necessarily increase the risk of superinfections; it is more about the spectrum of activity and the impact on normal flora.

Correct Answer: A

Rationale: Thiazide diuretics decrease urinary excretion of uric acid, leading to increased blood levels. Thiazides also increase potassium reabsorption, potentially causing hyperkalemia. However, the main effect on uric acid levels makes choice A correct. Choices B, C, and D are incorrect as thiazides do not directly impact BUN, urea, or glucose levels.

Correct Answer: D

Rationale: The correct answer is D: Conivaptan. Conivaptan is a non-peptide competitive antagonist of ADH, specifically targeting the V2 receptors in the collecting ducts of the nephron. This mechanism of action inhibits ADH's water-sparing effects, making it an effective treatment for SIADH. A: Mannitol is an osmotic diuretic used for conditions like cerebral edema and acute kidney injury, not specifically for SIADH. B: Bumetanide is a loop diuretic used for conditions like heart failure and hypertension, not for managing SIADH. C: Spironolactone is a potassium-sparing diuretic used for conditions like heart failure and hypertension, not for treating SIADH. In summary, Conivaptan is the correct choice for managing SIADH due to its specific mechanism of action as a competitive antagonist of ADH in the collecting ducts, while the other options are

Correct Answer: C

Rationale: Acetazolamide is a carbonic anhydrase inhibitor commonly used in treating glaucoma due to its ability to decrease intraocular pressure. The drug works by reducing the production of aqueous humor in the eye. This mechanism makes it an effective treatment for glaucoma. In contrast, liver cirrhosis (choice A) is typically managed with diuretics that act on the kidneys to reduce fluid accumulation. CHF (choice B) is commonly treated with loop diuretics to reduce fluid overload and improve cardiac function. Acetazolamide is not indicated for treating heart failure. Kidney failure (choice D) may require diuretics to manage fluid balance, but acetazolamide is not the first-line treatment in this condition. Therefore, the correct answer is C, as acetazolamide's current indication is in the treatment of glaucoma.