Cloxacillin is indicated in infections caused by the following organism(s) * a Staphylococci

Correct Answer: A

Rationale: Step-by-step rationale: 1. Cloxacillin is a beta-lactam antibiotic effective against Staphylococci. 2. Streptococci are not within the spectrum of activity for Cloxacillin. 3. Gonococci are also not susceptible to Cloxacillin. 4. Therefore, the correct answer is A (Streptococci), as Cloxacillin is indicated only for Staphylococcal infections. Summary: Choice A is correct because Cloxacillin is effective against Staphylococci. Choices B and C are incorrect because Cloxacillin is not indicated for Gonococci or all of the organisms mentioned.

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: A

Rationale: Step-by-step rationale for why A (Lamivudine) is correct: 1. Lamivudine is a nucleoside analog reverse transcriptase inhibitor used to treat chronic hepatitis B. 2. It inhibits the replication of the hepatitis B virus, reducing viral load and liver damage. 3. Clinical studies have shown its efficacy in improving liver function and reducing the risk of cirrhosis. 4. Lamivudine is recommended as a first-line treatment option by major medical guidelines. Summary of why other choices are incorrect: B. Human interferon α: While interferon therapy was previously used, it is no longer recommended as a first-line treatment due to its side effects and lower efficacy compared to newer drugs. C. Amantadine: Amantadine is not recommended for the treatment of chronic hepatitis B as it is not effective against the hepatitis B virus. D. (: This is not a valid drug option for treating chronic hepatitis B.

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.