The drug inhibits sodium and chloride transport in the cortical thick ascending limb and the early distal tubule:

Correct Answer: B

Rationale: The correct answer is B: Furosemide (Lasix). Furosemide is a loop diuretic that inhibits sodium and chloride transport in the cortical thick ascending limb. This leads to increased excretion of these ions and water. Acetazolamide (A) inhibits carbonic anhydrase in the proximal tubule, Hydrochlorothiazide (C) acts on the distal convoluted tubule, and Amiloride (D) inhibits sodium reabsorption in the collecting duct. Therefore, only Furosemide affects sodium and chloride transport in the cortical thick ascending limb.

Correct Answer: B

Rationale: The correct answer is B: Infections of urinary and gastrointestinal tracts. Nitrofuranes are commonly used to treat urinary tract infections and certain gastrointestinal infections due to their effectiveness against a variety of bacteria commonly found in these areas. Nitrofuranes are not typically used to treat respiratory infections (choice A), syphilis (choice C), or tuberculosis (choice D) as there are more appropriate antibiotics available for these conditions. Therefore, choice B is the correct indication for nitrofuranes based on their spectrum of activity and clinical effectiveness.

Correct Answer: C

Rationale: Step-by-step rationale: 1. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) bind to the enzyme reverse transcriptase. 2. Nevirapine is an NNRTI that inhibits HIV-1 reverse transcriptase. 3. Zidovudine (A) is a nucleoside reverse transcriptase inhibitor. 4. Vidarabine (B) is a nucleoside analog antiviral medication. 5. Gancyclovir (D) is a nucleoside analog antiviral used for herpesvirus infections. Summary: Choice C (Nevirapine) is the correct answer as it belongs to the class of NNRTIs by inhibiting reverse transcriptase enzyme. Choices A, B, and D are incorrect as they belong to the class of nucleoside analog antivirals, not NNRTIs.

Correct Answer: B

Rationale: Step 1: Nitroglycerin is a vasodilator commonly used to relieve angina symptoms. Step 2: Cellular tolerance can develop with prolonged nitroglycerin use, reducing its effectiveness. Step 3: In this case, the patient's anginal episodes suggest a diminished response to nitroglycerin. Step 4: This is supported by the fact that increasing metabolism (Choice C) or insufficient dosage (Choice D) would not explain the reduced efficacy. Step 5: Vasospasm (Choice A) would be less likely as the primary cause compared to cellular tolerance.

Correct Answer: B

Rationale: The correct answer is B, Diazoxide and hydralazine. Diazoxide is a vasodilator used to treat hypertension emergencies, while hydralazine is also a vasodilator commonly used for hypertensive crises. Both drugs have fast-acting properties and are often administered together to rapidly reduce blood pressure. A (Labetalol and prazosin) is incorrect because Labetalol is a beta-blocker and prazosin is an alpha-blocker, which are not commonly administered together for hypertensive emergencies. C (Clonidine and captopril) is incorrect because Clonidine is a centrally acting alpha-2 agonist and captopril is an ACE inhibitor, which are not typically used together for acute hypertension. D (Nitroprusside and esmolol) is incorrect because Nitroprusside is a potent vasodilator and esmolol is a beta-blocker, but they are not usually administered together