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 highlights the importance of understanding receptor-specific drug profiles in clinical settings. It covers alpha blockers like phentolamine and tamsulosin in managing conditions such as hypertension and benign prostatic hyperplasia, underscores the significance of receptor selectivity in beta blocker therapy for cardiac conditions, and explains the mechanism by which alkylating agents like cisplatin, cyclophosphamide, and mechlorethamine inflict DNA damage to suppress cancer cell replication.

Learning Objectives

1

Explain the mechanisms and clinical uses of receptor-specific drugs including alpha blockers, beta blockers, and alkylating antineoplastic agents.

2

Analyze how receptor selectivity influences therapeutic outcomes in both cardiac conditions and other diseases.

3

Compare and contrast the actions of different drug classes such as alpha blockers (phentolamine, tamsulosin) and beta blockers.

4

Describe the mechanism by which alkylating agents interfere with cancer cell replication through DNA cross-linking.

Key Concepts

CONCEPT

DEFINITION

Alpha Blockers

Drugs that inhibit alpha-adrenergic receptors, used to manage conditions like hypertension and benign prostatic hyperplasia by promoting smooth muscle relaxation.

Phentolamine

A non-selective alpha blocker used primarily for managing hypertensive crises by blocking alpha receptors.

Tamsulosin

A selective alpha-1A blocker that targets receptors in the prostate and bladder neck to relieve urinary symptoms associated with benign prostatic hyperplasia.

Beta Blockers

Medications that block beta-adrenergic receptors, reducing heart rate and contractility, and are used for treating various cardiac conditions including hypertension and arrhythmias.

Receptor Selectivity

The ability of a drug to selectively bind to specific receptor subtypes, which is critical for optimizing therapeutic effects while minimizing adverse outcomes.

Alkylating Agents

Chemotherapeutic drugs that interfere with cancer cell replication by forming covalent bonds with DNA, causing cross-links that inhibit cell division.

Cisplatin, Cyclophosphamide, Mechlorethamine

Examples of alkylating agents used in cancer treatment that work by causing DNA cross-linking, thereby impeding DNA replication in cancer cells.

Example Problems

Example 1

A patient is scheduled for colorectal surgery tomorrow. He does not have sepsis, his $\mathrm{WBC}$ count is normal, he has no fever, and he is otherwise in good health. However, there is an order to administer an antibiotic on call before he goes to surgery. The nurse knows that the rationale for this antibiotic order is to a provide empiric therapy. b provide prophylactic therapy. c treat for a superinfection. d reduce the number of resistant organisms.

Example 2

A teenage patient is taking a tetracycline drug as part of treatment for severe acne. When the nurse teaches this patient about drug-related precautions, which is the most important information to convey? a When the acne clears up, the medication may be discontinued. b This medication needs to be taken with antacids to reduce GI upset. $c$ The patient needs to use sunscreen or avoid exposure to sunlight, because this drug may cause photosensitivity. d The teeth should be observed closely for signs of mottling or other color changes.

Example 3

A newly admitted patient reports a penicillin allergy. The prescriber has ordered a second-generation cephalosporin as part of the therapy. Which nursing action is appropriate? a Call the prescriber to clarify the order because of the patient's allergy. b Give the medication, and monitor for adverse effects. c Ask the pharmacy to change the order to a first-generation cephalosporin. d Administer the drug with a nonsteroidal antiinflammatory drug to reduce adverse effects.

Example 4

During patient education regarding an oral macrolide such as erythromycin, the nurse will include which information? a If GI upset occurs, the drug will have to be stopped. b The drug needs to be taken with an antacid to avoid GI problems. $c$ The patient needs to take each dose with a sip of water. d The patient may take the drug with a small snack to reduce GI irritation.

Example 5

A woman who has been taking an antibiotic for a UTI calls the nurse practitioner to complain of severe vaginal itching. She has also noticed a thick, whitish vaginal discharge. The nurse practitioner suspects that a this is an expected response to antibiotic therapy. b the UTI has become worse instead of better. $c$ a superinfection has developed. d the UTI is resistant to the antibiotic.
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Step-by-Step Explanations

QUESTION

How does tamsulosin alleviate urinary symptoms in benign prostatic hyperplasia (BPH)?

STEP-BY-STEP ANSWER:

Step 1: Identify the target tissue – the prostate and bladder neck possess alpha-1A receptors that regulate muscle tone.
Step 2: Recognize that tamsulosin selectively binds to these alpha-1A receptors.
Step 3: Understand that binding leads to relaxation of smooth muscle in these areas.
Step 4: Relate that muscle relaxation improves urinary flow and reduces BPH symptoms.
Final Answer: Tamsulosin alleviates BPH symptoms by selectively blocking alpha-1A receptors, leading to smooth muscle relaxation and improved urinary flow.

Alpha Blockers

QUESTION

How does receptor selectivity in beta blockers affect their clinical utility in managing cardiac conditions?

STEP-BY-STEP ANSWER:

Step 1: Distinguish between beta-1 and beta-2 adrenergic receptors – beta-1 receptors are primarily located in the heart, while beta-2 receptors are found in the lungs and vasculature.
Step 2: Understand that beta blockers with high beta-1 selectivity primarily affect cardiac tissue, reducing heart rate and myocardial contractility.
Step 3: Recognize that this selectivity minimizes unwanted side effects in other tissues (like bronchoconstriction in the lungs).
Step 4: Conclude that selective beta blockers are preferable in patients with concurrent respiratory issues.
Final Answer: Receptor selectivity in beta blockers ensures targeted cardiac effects and minimizes adverse effects on other organs, enhancing clinical safety and efficacy in managing heart conditions.

Beta Blockers

QUESTION

Explain the mechanism by which alkylating agents such as cisplatin interfere with cancer cell replication.

STEP-BY-STEP ANSWER:

Step 1: Understand that alkylating agents add alkyl groups to the DNA molecule.
Step 2: Recognize that this addition leads to the formation of covalent bonds within or between DNA strands (DNA cross-linking).
Step 3: Note that cross-linked DNA strands hinder the processes of DNA replication and transcription.
Step 4: Explain that the inability to properly replicate DNA eventually triggers cell death in rapidly dividing cancer cells.
Final Answer: Alkylating agents disrupt cancer cell replication by forming covalent bonds that cross-link DNA strands, thereby halting DNA synthesis and inducing cell death.

Alkylating Agents

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Common Mistakes

  • Confusing the roles of alpha blockers and beta blockers, and not recognizing their different target receptors.
  • Assuming all beta blockers have the same receptor selectivity, which can lead to inappropriate clinical applications.
  • Overgeneralizing the mechanism of alkylating agents without understanding the specificity of DNA cross-linking.
  • Failing to appreciate the clinical implications of receptor selectivity, thereby misjudging potential side effects.