Which of the following anti-HIV regimen that is generally reserved for * advanced cases of AIDS or for repeated treatment failures?:

Correct Answer: A

Rationale: The correct answer is A: Two nucleoside reverse transcriptase inhibitors (NRTIs) + one protease inhibitor (PI). This regimen is typically reserved for advanced cases of AIDS or repeated treatment failures due to its potent antiviral effects. NRTIs inhibit viral replication by interfering with the HIV enzyme reverse transcriptase, while PIs inhibit the enzyme protease, essential for viral maturation. Combining these two classes of drugs provides a strong barrier against HIV resistance. Other choices (B, C, D) are less effective in advanced cases as they do not provide the same level of dual inhibition necessary to combat resistant strains and advanced disease progression.

Correct Answer: B

Rationale: The correct answer is B: Primaquine. Primaquine is a radical curative drug for Plasmodium vivax malaria, as it targets the hypnozoite stage in the liver, preventing relapses. It is also used as prophylaxis in Chloroquine-sensitive regions due to its efficacy against P. vivax and P. ovale. Rationale: 1. Quinine (A) is not a radical curative drug for P. vivax malaria. It is mainly used for treatment of acute malaria. 2. Meoquine (C) is not a radical curative drug for P. vivax malaria and is used more for prophylaxis in certain regions. 3. Chloroquine (D) is not a radical curative drug for P. vivax malaria and is primarily used for treatment and prevention of malaria caused by susceptible strains of Plasmodium species.

Correct Answer: D

Rationale: Step 1: Piperacillin is a semisynthetic penicillin with extended spectrum against gram-negative bacilli. Step 2: It is acid-resistant, meaning it can withstand acidic environments in the stomach. Step 3: However, it is not penicillinase-resistant, making it susceptible to penicillinase enzymes. Step 4: Cloxacillin (A) and Amoxicillin (B) are penicillinase-resistant but do not have extended gram-negative activity. Step 5: Phenoxymethyl penicillin (C) is neither acid-resistant nor penicillinase-resistant. In summary, Piperacillin is the correct choice due to its extended spectrum against gram-negative bacilli and acid resistance, despite not being penicillinase-resistant.

Correct Answer: C

Rationale: The correct answer is C: Hydrochlorothiazide. Hydrochlorothiazide is a thiazide diuretic that can lead to hyperuricemia, a risk factor for gout. Thiazide diuretics decrease the excretion of uric acid, leading to its accumulation and potential for gout attacks. Furosemide (A) is a loop diuretic that does not have a significant impact on uric acid levels. Spironolactone (B) and Triamterene (D) are potassium-sparing diuretics and do not directly affect uric acid levels. So, Hydrochlorothiazide is the most likely diuretic causing the gout attack in this case.

Correct Answer: C

Rationale: Furosemide inhibits the Na+K+/2Cl- transporter in the renal tubular cell. This transporter is responsible for reabsorbing sodium, potassium, and chloride ions from the urine back into the bloodstream. By inhibiting this transporter, furosemide prevents the reabsorption of these ions, leading to increased excretion of water and electrolytes, thereby promoting diuresis. Na+K+ ATPase (A) is not the target of furosemide. Na+/Cl- transporter (B) is not the primary mechanism of action for furosemide. Na+H+ antiporter (D) is not the target of furosemide in the renal tubular cell.