Book cover for Pharmacology and the Nursing Process

Pharmacology and the Nursing Process

Linda Lane Lilley, Shelly Rainforth Collins, Julie S. Snyder

ISBN #9780323087896

7th Edition

394 Questions

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2,697 Students Helped

Homework Questions

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Summary
Learning Objectives
Key Concepts
Example Problems
Explanations
Common Mistakes

Summary

This chapter delves into the complexities of treating multidrug-resistant infections, highlighting the critical role of understanding both the pathophysiology of resistant organisms and the pharmacological frameworks that guide antimicrobial therapy. Emphasis is placed on core concepts such as MIC and the postantibiotic effect, alongside the importance of carefully constructed drug profiles that consider toxicity and interaction risks. Together, these elements provide a comprehensive strategy for effectively managing serious infections in clinical practice.

Learning Objectives

1

Explain the pathophysiology and challenges associated with multidrug-resistant infections such as MRSA, VRE, ESBL, and KPC.

2

Analyze the importance of pharmacokinetic and pharmacodynamic properties in designing effective antimicrobial therapy.

3

Apply concepts like Minimum Inhibitory Concentration (MIC) and the postantibiotic effect to determine accurate dosing strategies.

4

Evaluate drug profiles with an emphasis on monitoring potential toxicities and drug interactions.

5

Implement preventive measures to curb the spread of antimicrobial resistance in clinical settings.

Key Concepts

CONCEPT

DEFINITION

MRSA

Methicillin-resistant Staphylococcus aureus, a type of bacteria that is resistant to many antibiotics commonly used to treat staph infections.

VRE

Vancomycin-resistant Enterococcus, bacteria that have developed resistance to vancomycin, a key antibiotic used to treat infections.

ESBL

Extended-Spectrum Beta-Lactamases, enzymes produced by certain bacteria that confer resistance to a wide variety of beta-lactam antibiotics.

KPC

Klebsiella pneumoniae Carbapenemase, an enzyme that makes bacteria resistant to carbapenem antibiotics, often used as a last line of defense.

Pharmacokinetics

The study of how a drug is absorbed, distributed, metabolized, and excreted by the body.

Pharmacodynamics

The study of the biochemical and physiological effects of drugs and their mechanisms of action, including the relationship between drug concentration and effect.

Minimum Inhibitory Concentration (MIC)

The lowest concentration of an antimicrobial agent that prevents the visible growth of a microorganism.

Postantibiotic Effect

The period of time after antibiotic exposure during which bacterial growth remains inhibited even after antibiotic levels have fallen below the MIC.

Drug Profile

The comprehensive characteristics of a drug including its pharmacokinetics, pharmacodynamics, potential toxicities, and interactions.

Example Problems

Example 1

While assessing a woman who is receiving an antibiotic for community acquired pneumonia, the nurse notes that the patient has a thick, white vaginal discharge. The patient is also complaining about perineal itching. The nurse suspects that the patient has a resistance to the antibiotic. b an adverse effect of the antibiotic. $\mathrm{c}$ a superinfection. d an allergic reaction.

Example 2

A patient has been admitted for treatment of an infected leg ulcer and will be started on intravenous linezolid. The nurse is reviewing the list of the patient's current medications. Which type of medication, if listed, would be of most concern if taken with the linezolid? a Beta blocker b Oral anticoagulant c Selective serotonin reuptake inhibitor antidepressant d Thyroid replacement hormone

Example 3

When administering vancomycin, the nurse knows that which of these is most important to assess before giving the medication? a Renal function b WBC count c Liver function d Platelet count

Example 4

During therapy with an intravenous aminoglycoside, the patient calls the nurse and says, "I'm hearing some odd sounds, like ringing, in my ears." What is the nurse's priority action at this time? a Reassure the patient that these are expected adverse effects. b Reduce the rate of the intravenous infusion. c Increase the rate of the intravenous infusion. d Stop the infusion immediately.

Example 5

When giving intravenous quinolones, the nurse needs to keep in mind that these drugs may have serious interactions with which drugs? a Selective serotonin reuptake inhibitor antidepressants b Nonsteroidal antiinflammatory drugs $c$ Oral anticoagulants d Antihypertensives
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Step-by-Step Explanations

QUESTION

How do you determine an effective antibiotic dosing regimen using the concept of MIC?

STEP-BY-STEP ANSWER:

Step 1: Identify the pathogen and obtain its MIC value from laboratory data.
Step 2: Assess the pharmacokinetic properties of the antibiotic to determine achievable drug concentrations in the body.
Step 3: Compare the MIC value with the peak and trough concentrations that can be safely achieved.
Step 4: Adjust the dosing regimen to ensure that drug levels remain above the MIC for an adequate duration.
Final Answer: Use the MIC in conjunction with pharmacokinetic data to tailor the dosing schedule to maintain effective antibiotic levels.

Determining Appropriate Dosing Using MIC

QUESTION

How can the postantibiotic effect influence the dosing intervals of antibiotics?

STEP-BY-STEP ANSWER:

Step 1: Determine the duration of the postantibiotic effect for the chosen antibiotic.
Step 2: Understand that after the antibiotic concentration falls below the MIC, bacterial growth may still be suppressed.
Step 3: Factor in the length of this effect when scheduling the next dose to avoid unnecessary dosing.
Step 4: Adjust the dosing intervals to optimize efficacy while minimizing toxicity and resistance development.
Final Answer: Use the postantibiotic effect to guide longer dosing intervals, ensuring continued bacterial inhibition while reducing potential side effects.

Utilizing the Postantibiotic Effect

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Common Mistakes

  • Failing to integrate both pharmacokinetic and pharmacodynamic principles when determining dosing regimens.
  • Overlooking the significance of the postantibiotic effect, leading to unnecessarily frequent dosing.
  • Misinterpreting MIC values by not correlating them with achievable drug concentrations in the body.
  • Underestimating the risk of toxicities and interactions associated with certain antimicrobial agents.
  • Neglecting preventive measures that can help curb the spread of antimicrobial resistance.