Nokea
Which of the following semisynthetic penicillins which has an extended spectrum of activity against many gram negative bacilli, is acid resistant but not penicillinase resistant?:
- A. Cloxacillin
- B. Amoxicillin
- C. Phenoxymethyl penicillin
- D. Piperacillin
Correct Answer: B
Rationale: The correct answer is B: Amoxicillin. This penicillin has an extended spectrum of activity against gram-negative bacilli, making it effective against a wider range of bacteria. It is acid-resistant, allowing it to be taken orally, but it is not penicillinase-resistant, meaning it can be easily degraded by beta-lactamase enzymes.
A: Cloxacillin is penicillinase-resistant but does not have an extended spectrum against gram-negative bacilli.
C: Phenoxymethyl penicillin is not acid-resistant and does not have an extended spectrum against gram-negative bacilli.
D: Piperacillin has an extended spectrum of activity but is not acid-resistant and is susceptible to penicillinase.
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During a vaginal examination of a 38-year-old woman, the nurse notices that the vulva and vagina are erythematous and edematous with thick, white, curdlike discharge adhering to the vaginal walls. The woman reports intense pruritus and thick white discharge from her vagina. The nurse knows that these history and physical examination findings are most consistent with which condition?
- A. Candidiasis
- B. Trichomoniasis
- C. Atrophic vaginitis
- D. Bacterial vaginosis
Correct Answer: A
Rationale: Step 1: The key clues in the question are thick, white, curdlike discharge, intense pruritus, erythematous, and edematous vulva and vagina.
Step 2: These symptoms are classic for candidiasis, a fungal infection caused by Candida species.
Step 3: Candidiasis commonly presents with thick, white discharge, itching, and inflamed vaginal tissues.
Step 4: Trichomoniasis (choice B) typically presents with frothy, greenish-yellow discharge and vaginal itching.
Step 5: Atrophic vaginitis (choice C) is more common in postmenopausal women and presents with thin, watery discharge and vaginal dryness.
Step 6: Bacterial vaginosis (choice D) presents with thin, grayish-white discharge and a fishy odor.
Step 7: Therefore, based on the symptoms described in the question, the correct answer is A: Candidiasis.
Which statement best describes Zidovudine:
- A. Zidovudine in combination with other antiretrovirals is an alternative initial treatment for HIV infection
- B. Zidovudine is also used to prevent transmission of HIV from the mother to her fetus and to treat AIDS-related dementia
- C. Peripheral neuropathy is a specific adverse reaction to Zidovudine
- D. Zidovudine is converted by cellular enzymes to an active form
Correct Answer: zidovudine diphosphate
Rationale: The correct answer is D: Zidovudine is converted by cellular enzymes to an active form (zidovudine diphosphate). Zidovudine itself is a prodrug that needs to be metabolized by cellular enzymes to its active form, zidovudine diphosphate, which inhibits HIV replication by acting as a nucleoside reverse transcriptase inhibitor. This active form is essential for its antiretroviral activity.
Incorrect Choices:
A: Zidovudine in combination with other antiretrovirals is an alternative initial treatment for HIV infection - This is incorrect because zidovudine is commonly used in combination with other antiretrovirals as a first-line treatment for HIV infection, not as an alternative treatment.
B: Zidovudine is also used to prevent transmission of HIV from the mother to her fetus and to treat AIDS-related dementia - This is incorrect because zidovudine is primarily used in
Red man syndrome has been associated with rapid intravenous injection of which of the following antibiotic?
- A. Vancomycin
- B. Clindamycin
- C. Cefoperazone
- D. Piperacillin
Correct Answer: A
Rationale: The correct answer is A: Vancomycin. Red man syndrome is a type of hypersensitivity reaction associated with rapid intravenous infusion of vancomycin. This is due to the release of histamine from mast cells and basophils. Vancomycin is known to cause this syndrome, while the other antibiotics listed do not have a similar association. Clindamycin is more commonly associated with pseudomembranous colitis, Cefoperazone with liver toxicity, and Piperacillin with hypersensitivity reactions like rash or anaphylaxis. Therefore, based on the mechanism of action and clinical evidence, vancomycin is the correct choice for causing red man syndrome.
A 70 year old man requires treatment with an alpha-blocker for overflow incontinence due to enlarged prostate. Which of the following alpha blocking drugs is most appropriate drug to prescribe that will not affect his blood pressure significantly?
- A. Prazosin
- B. Phentolamine
- C. Tamsulosin
- D. Terazosin
Correct Answer: C
Rationale: The correct answer is C: Tamsulosin. It is the most appropriate alpha-blocker for the elderly man with enlarged prostate and overflow incontinence because of its selective action on alpha-1A receptors in the prostate, leading to relaxation of smooth muscle without significantly affecting blood pressure.
Rationale:
1. Prazosin (Choice A) and Terazosin (Choice D) are non-selective alpha-blockers that can cause significant blood pressure lowering due to their action on alpha-1 receptors in blood vessels, which may not be suitable for this patient.
2. Phentolamine (Choice B) is also a non-selective alpha-blocker that can lead to significant blood pressure reduction, making it unsuitable for this patient.
3. Tamsulosin (Choice C) is a selective alpha-1A blocker, primarily acting on the prostate, with minimal impact on blood pressure, making it the most appropriate choice for this patient.
Which of the following is true of nephrons?
- A. they are the functional units of the kidneys
- B. the proximal convoluted tubules allow the kidney to concentrate or dilute urine
- C. there are about a million nephrons in each kidney
- D. both a and c are correct
Correct Answer: D
Rationale: Step 1: Identify key characteristics of nephrons - functional units of kidneys, responsible for urine formation.
Step 2: Confirm accuracy of statements - A: Nephrons are functional units. C: About a million nephrons in each kidney.
Step 3: Combine statements - A + C = D, confirming both are correct.
Step 4: Justify choice D - correct because nephrons are indeed functional units and there are approximately a million in each kidney.
Summary: B is incorrect as the proximal convoluted tubules are not solely responsible for urine concentration/dilution. Choice D is correct as it combines the accurate statements from A and C.