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 section provides a detailed overview of several key drug profiles including alpha blockers, beta blockers, and alkylating agents. It highlights the specific roles of phentolamine in managing conditions such as pheochromocytoma and extravasation injuries, and of tamsulosin in alleviating urinary issues in BPH. In addition, the text underlines the cardiac benefits of beta blockers and the cancer cell-targeting mechanism of alkylating agents like cisplatin. A comprehensive understanding of pharmacokinetics, contraindications, and drug interactions is emphasized as essential to safely and effectively using these medications.

Learning Objectives

1

Describe the pharmacological profiles and mechanisms of action of alpha blockers, beta blockers, and alkylating agents.

2

Explain the therapeutic uses of phentolamine and tamsulosin, including their roles in treating pheochromocytoma, extravasation injuries, and BPH.

3

Understand how beta blockers reduce cardiac workload and how alkylating agents like cisplatin destroy cancer cells.

4

Analyze the importance of pharmacokinetics, contraindications, and drug interactions for the safe use of these medications.

Key Concepts

CONCEPT

DEFINITION

Alpha Blockers

A class of drugs that relax certain muscles and help small blood vessels remain open, often used in diagnosing and treating conditions like pheochromocytoma.

Beta Blockers

Medications that reduce heart rate and cardiac workload by blocking the effects of adrenaline on the heart.

Alkylating Agents

Chemotherapeutic drugs, such as cisplatin, that work by cross-linking DNA, leading to the destruction of rapidly dividing cancer cells.

Phentolamine

An alpha blocker used primarily in diagnosing and treating pheochromocytoma and extravasation injuries.

Tamsulosin

A selective alpha blocker used to improve urinary flow in patients with benign prostatic hyperplasia (BPH).

Pharmacokinetics

The study of how drugs are absorbed, distributed, metabolized, and excreted in the body.

Contraindications

Specific situations or conditions where a particular drug should not be used due to potential harm.

Drug Interactions

The effects that may occur when one drug influences the activity of another when both are administered together.

Example Problems

Example 1

When assessing a patient who will be receiving a measles vaccine, the nurse will consider which condition to be a possible contraindication? a Anemia b Pregnancy c Ear infection d Common cold

Example 2

When giving a vaccination to an infant, the nurse should tell the mother to expect which adverse effect? a Fever over $101^{\circ} \mathrm{F}\left(38.3^{\circ} \mathrm{C}\right)$ b Rash $c$ Soreness at the injection site d Chills

Example 3

In the emergency department, several patients have possibly been exposed to anthrax. The nurse will prepare to administer prophylactic doses of a ciprofloxacin. b cidofovir. c immunoglobulin. d antitoxin.

Example 4

During a routine checkup, a 72-year-old patient is advised to receive an influenza vaccine injection. He questions this, saying, "I had one last year. Why do I need another one?" What is an appropriate response from the nurse? a "The effectiveness of the vaccine wears off after 6 months." b "Each year a new vaccine is developed based on the flu strains that are likely to be in circulation." c "When you reach 65 years of age, you need boosters on an annual basis." d "Taking the flu vaccine each year allows you to build your immunity to a higher level each time."

Example 5

A 28-year-old is in the urgent care center after stepping on a rusty tent nail. The nurse evaluates the patient's immunity status and notes that the patient thinks she had her last tetanus booster about 10 years ago, just before starting college. Which immunization would be most appropriate at this time? a Immunoglobulin intravenous (Gammar-P IV) b DTaP (Daptacel) (diphtheria, tetanus, and acellular pertussis) c Tdap (Adacel) (diphtheria, tetanus, and acellular pertussis) d No immunizations are necessary at this time.
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Step-by-Step Explanations

QUESTION

How does phentolamine help in diagnosing and treating pheochromocytoma?

STEP-BY-STEP ANSWER:

Step 1: Recognize that pheochromocytoma is a condition characterized by excessive catecholamine secretion due to adrenal tumors.
Step 2: Understand that phentolamine, as an alpha blocker, inhibits the action of catecholamines, which can relieve the symptoms of high blood pressure and other related symptoms.
Step 3: Note that the administration of phentolamine can provide diagnostic clues based on the improvement in symptoms and blood pressure regulation.
Final Answer: Phentolamine is used to block the action of catecholamines in pheochromocytoma, thereby aiding in both diagnosis and treatment by alleviating symptoms and controlling hypertension.

Use of Phentolamine in Pheochromocytoma

QUESTION

How does tamsulosin improve urinary flow in patients with benign prostatic hyperplasia?

STEP-BY-STEP ANSWER:

Step 1: Understand that benign prostatic hyperplasia (BPH) involves enlargement of prostate tissue, which constricts the urethra and impedes urinary flow.
Step 2: Realize that tamsulosin is a selective alpha blocker that targets receptors in the prostate and bladder neck.
Step 3: Recognize that by relaxing these muscles, tamsulosin decreases urethral resistance and improves urine flow.
Final Answer: Tamsulosin works by selectively blocking alpha receptors in the prostate and bladder neck, thereby relaxing the muscles to improve urinary flow in BPH patients.

Mechanism of Tamsulosin in BPH

QUESTION

What is the primary mechanism by which beta blockers reduce cardiac workload?

STEP-BY-STEP ANSWER:

Step 1: Note that beta blockers prevent adrenaline from binding to beta receptors in the heart.
Step 2: Understand this leads to a decrease in heart rate and force of contraction.
Step 3: Recognize that the reduction in heart rate and contractility lowers the overall cardiac workload and oxygen demand.
Final Answer: Beta blockers reduce cardiac workload primarily by lowering heart rate and contractility through inhibition of beta-adrenergic receptors.

Beta Blockers' Role in Cardiac Workload Reduction

QUESTION

How do alkylating agents like cisplatin work in the treatment of cancer?

STEP-BY-STEP ANSWER:

Step 1: Understand that alkylating agents interact directly with DNA within the cancer cells.
Step 2: Recognize that cisplatin forms cross-links in the DNA, interfering with replication and transcription.
Step 3: Note that this damage ultimately leads to cell death, particularly in rapidly dividing cancer cells.
Final Answer: Alkylating agents such as cisplatin destroy cancer cells by cross-linking DNA, disrupting cell division and leading to cell death.

Action of Alkylating Agents (Cisplatin) in Cancer Therapy

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Common Mistakes

  • Assuming all beta blockers have the same intensity of effect regardless of dosage or patient condition.
  • Misinterpreting the mechanism of action of phentolamine solely as a blood pressure reducer without recognizing its diagnostic applications.
  • Overlooking the importance of drug interactions and contraindications when using potent agents like cisplatin.
  • Confusing the role of alpha blockers in BPH with their application in other vascular conditions, leading to improper treatment plans.