NCLEX : Antimicrobial Pharmacology

Study concepts, example questions & explanations for NCLEX

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Example Questions

Example Question #11 : Antimicrobial Pharmacology

Which of the following antibiotics is least likely to cause C. difficile overgrowth and C. difficile associated diarrhea?

Possible Answers:

Vancomycin

Amoxicillin

Ampicillin

Clindamycin

Correct answer:

Vancomycin

Explanation:

All of the drugs listed frequently cause C. difficile overgrowth and C. difficile associated diarrhea except vancomycin, which is often used as a treatment for persistent C. difficile infections.

Example Question #11 : Antimicrobial Pharmacology

Which of the following antibiotics is contraindicated in pregnant women and small children due to it's tendency to irreversibly stain developing teeth?

Possible Answers:

Aminoglycosides

Fluoroquinolones

Beta lactam antibiotics

Tetracyclines

Correct answer:

Tetracyclines

Explanation:

Tetracycline antibiotics are contraindicated in pregnant women and small children due to their tendency to irreversibly stain developing teeth. They can also affect fetal bone growth and so are pregnancy category D (known incidence and risk of fetal harm).

Example Question #11 : Antimicrobial Pharmacology

Which of the following antibiotics is considered safe in pregnancy?

Possible Answers:

Gentamicin

Doxycycline

Amoxicillin

Levofloxacin

Correct answer:

Amoxicillin

Explanation:

Of the antibiotics listed, amoxicillin is the only one considered safe in pregnancy. Doxycycline and gentamicin are both pregnancy category D (known to cause fetal harm). Levofloxacin is category C (fetal harm can not be ruled out).

Example Question #11 : Antimicrobial Pharmacology

Penicillin us used to treat what type of microbe?

Possible Answers:

Gram positive bacteria only

Fungal infections

Gram positive and Gram negative

Gram negative bacteria only

Correct answer:

Gram positive bacteria only

Explanation:

Penicillins belong to a larger class of antibiotics known as beta-lactams. These antibiotics inhibit cell-wall synthesis and are exclusively used to treat Gram positive bacteria. They are not effective against Gram negative bacteria or fungi. 

Example Question #142 : Nclex

Which of the following class of antibiotics is considered the first-line treatment for E. coli infections?

Possible Answers:

Fluoroquinolones

Tetracyclines

Aminoglycosides

Macrolides

Correct answer:

Fluoroquinolones

Explanation:

Fluoroquinolones are considered to be the treatment of choice for E. coli infections due to their effectiveness in relieving diarrhea and minimal serious adverse effects. Aminoglycosides and beta-lactam antibiotics may also be effective, as a second choice.

Example Question #11 : Antimicrobial Pharmacology

The nurse considers administration of gentamycin. Which of the following is not a side effect of this medication?

Possible Answers:

Anorexia

Ototoxicity

Nausea

Nephrotoxicity

Diaphoresis

Correct answer:

Diaphoresis

Explanation:

Gentamycin, an antibiotic and aminoglycoside, inhibits protein synthesis of gram-negative bacteria. It treats severe systemic infections. It may cause ototoxicity and nephrotoxicity, as well as anorexia, nausea, vomiting, and diarrhea. Diaphoresis is not a common side effect of gentamycin.

Example Question #151 : Pharmacology

You are the nurse taking care of a patient who is being treated with levofloxacin, a fluoroquinolone antibiotic, for pneumonia. Which of the following choices best describes the mechanism of action of fluoroquinolone antibiotics?

Possible Answers:

Disruption of peptidoglycan cross-linkage

Inhibition of topoisomerase II

Disruption of mycolic acid synthesis

Inhibition of peptidoglycan synthesis

Blockage of tRNA-ribosome-mRNA complex binding

Correct answer:

Inhibition of topoisomerase II

Explanation:

The correct answer is "inhibition of topoisomerase II," as this is the mechanism of action of fluoroquinolone antibiotics, such as levofloxacin.

The other choices are incorrect for the following reasons:

Blockage of tRNA-ribosome-mRNA complex binding is the mechanism of action of tetracycline antibiotics. 

Disruption of mycolic acid synthesis is the mechanism of action of various anti-fungal agents.

Disruption of peptidoglycan cross-linkage is the mechanism of action of vancomycin.

Inhibition of peptidoglycan synthesis is the mechanism of action of beta-lactam antibiotics.

Example Question #151 : Pharmacology

You start a 32 year-old, HIV + Caucasian male on acyclovir (Zovirax) for a herpes simplex virus (HSV) infection. What is the mechanism of action of acyclovir?

Possible Answers:

Acyclovir is phosphorylated by viral thymidine kinase and used as a defective guanosine analog in viral DNA synthesis.

Acyclovir serves as a "cap" to viral mRNA and prevents binding of reverse transcriptase.

Acyclovir binds to ICAM-1, preventing viral attachment

Acyclovir binds to the hydrophobic sites on the influenza virus capsule. This destabilizes the virus, not allowing it to attach to the cell

Acyclovir prevents viral uncoating and inhibits production of viral mRNA.

Correct answer:

Acyclovir is phosphorylated by viral thymidine kinase and used as a defective guanosine analog in viral DNA synthesis.

Explanation:

Acyclovir is converted to acyclovir-triphosphate and incorporated into the synthetic pathway for viral DNA as a guanosine molecule. The initial phosphorylation of acyclovir is carried out by viral thymidine kinase. Acyclovir has a higher affinity for viral thymidine kinase than mammalian thymidine kinase. Therefore, acyclovir is specifically effective in virally infected cells.

Example Question #11 : Antimicrobial Pharmacology

Identify the anti-viral agent that blocks assembly of pox viruses by inhibiting viral protein synthesis.

Possible Answers:

Dideoxyinosine

Phosphonoacetic acid

Azidothymidine

Methisazone

Amantadine

Correct answer:

Methisazone

Explanation:

Methisazone blocks synthesis of viral mRNA and proteins. This is especially evident in pox viruses. Methisazone has been used to treat small pox.

Example Question #154 : Pharmacology

You are prophylactically treating a 84 year-old Caucasian male with amantadine and vaccination for avoidance of an upcoming influenza outbreak. The patient is to receive 100 mg b.i.d. for eight days. What potential side-effects would you look for with amantadine toxicity?

Possible Answers:

Hyperbilirubinemia, nausea, jaundice

Low blood pressure, bradycardia, premature ventricular contractions

Nervousness, insomnia, anxiety

Elevated BUN, hematuria, nausea

Leukopenia, anemia, increased susceptibility to infection

Correct answer:

Nervousness, insomnia, anxiety

Explanation:

Amantadine affects the central nervous system, producing mild, reversible disturbances. High dosages have been reported to induce seizures

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