Nokea
Which one of the following bactericidal antimycobacterial drugs binds to S12 * ribosomal subunit inhibiting protein synthesis when injectable drug is needed and also effective against drug-resistant tuberculosis drug, can cause ototoxicity and nephrotoxicity?
- A. Streptomycin
- B. Ethambutol
- C. Isoniazid
- D. Rifampicin
Correct Answer: A
Rationale: The correct answer is A: Streptomycin. Streptomycin binds to the S12 ribosomal subunit, inhibiting protein synthesis in Mycobacterium tuberculosis. It is effective against drug-resistant tuberculosis and is used as an injectable drug. Streptomycin can cause ototoxicity and nephrotoxicity as side effects.
Choice B: Ethambutol primarily inhibits cell wall synthesis and can cause optic neuritis.
Choice C: Isoniazid inhibits mycolic acid synthesis and can cause hepatotoxicity.
Choice D: Rifampicin inhibits DNA-dependent RNA polymerase and can cause hepatotoxicity and drug interactions.
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Which of the following interferes with mycolic acid synthesis an essential component of mycobacterial cell walls for which resistance will develop rapidly if the drug is used alone?
- A. Isoniazid
- B. Rifampicin
- C. Pyrazinamide
- D. Ethanbutol
Correct Answer: A
Rationale: The correct answer is A: Isoniazid. Isoniazid inhibits the synthesis of mycolic acid, a crucial component of mycobacterial cell walls. If used alone, resistance can develop rapidly due to its specific mechanism of action. Rifampicin (B) acts on RNA polymerase, not mycolic acid synthesis. Pyrazinamide (C) targets mycobacteria in acidic environments, not mycolic acid. Ethambutol (D) inhibits arabinosyltransferase, not mycolic acid synthesis.
The renin-angiotensin-aldosterone system (RAAS) is essential in regulating blood pressure. Which of the following hormones involved in RAAS is produced by the kidney?
- A. Renin
- B. Angiotensin I
- C. Angiotensin II
- D. Aldosterone
Correct Answer: A
Rationale: Rationale: Renin is produced and released by the kidney in response to low blood pressure or low sodium levels. Renin initiates the RAAS cascade by converting angiotensinogen to angiotensin I. Angiotensin I is then converted to angiotensin II, leading to vasoconstriction and aldosterone release. Aldosterone, produced by the adrenal glands, promotes sodium and water retention. Therefore, choice A is correct as renin is the hormone produced by the kidney to regulate blood pressure. Choices B, C, and D are incorrect as they are downstream products of the RAAS cascade and are not directly produced by the kidney.
A 70 year old man has severe urinary hesitancy associated with BPH. He has tried alpha blockers with little effect. His physician recommends a drug that blocks 5α-reductase in the prostate which is:
- A. Leuprolide
- B. Finasteride
- C. Flutamide
- D. Ketoconazole
Correct Answer: B
Rationale: The correct answer is B: Finasteride. Finasteride is a 5α-reductase inhibitor that reduces the conversion of testosterone to dihydrotestosterone in the prostate, thereby shrinking the prostate gland and improving urinary symptoms in BPH. Leuprolide (A) is a GnRH agonist used in prostate cancer, not BPH. Flutamide (C) is an antiandrogen used in prostate cancer. Ketoconazole (D) is an antifungal drug and not indicated for BPH.
A 22-year-old woman has been considering using oral contraceptives. As a part of her health history, the nurse should ask:
- A. Do you have a history of heart murmurs?
- B. Will you be in a monogamous relationship?
- C. Have you carefully thought this choice through?
- D. If you smoke, how many cigarettes do you smoke per day?
Correct Answer: D
Rationale: The correct answer is D because smoking increases the risk of cardiovascular complications with oral contraceptives. By asking about the number of cigarettes smoked per day, the nurse can assess the level of risk. Choice A is incorrect as it is not directly related to the safety of oral contraceptives. Choice B is important for overall sexual health but not directly related to the safety of oral contraceptives. Choice C is vague and does not provide specific information about potential risks associated with oral contraceptives.
Antiviral agents that is/ are active against cytomegalovirus (CMV) include * which of the following?
- A. Ganciclovir
- B. Foscarnet
- C. Acyclovir
- D. (
Correct Answer: A
Rationale: Step-by-step rationale for choice A (Ganciclovir) being the correct answer:
1. Ganciclovir is a nucleoside analog that inhibits CMV DNA synthesis.
2. It is specifically approved for the treatment of CMV retinitis in immunocompromised patients.
3. Ganciclovir has a high specificity for CMV, making it an effective antiviral agent against CMV.
Summary of why the other choices are incorrect:
- Choice B (Foscarnet) is also active against CMV but is not as commonly used as Ganciclovir.
- Choice C (Acyclovir) is not effective against CMV as it primarily targets herpes simplex virus and varicella-zoster virus.
- Choice D ( ) is an incomplete choice and does not correspond to any known antiviral agent.