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 on Drug Profiles provides an overview of three major classes of drugs: alpha blockers, beta blockers, and alkylating agents. It emphasizes their mechanisms of action, clinical applications, and the importance of understanding pharmacokinetics and drug interactions. The distinctions between cardioselective and nonselective beta blockers are particularly notable, as they directly impact patient safety and treatment outcomes. Effective clinical use of these drugs requires careful attention to contraindications and potential interactions.

Learning Objectives

1

Describe the mechanism of action, pharmacokinetics, and clinical uses of alpha blockers, beta blockers, and alkylating agents.

2

Differentiate between cardioselective and nonselective beta blockers based on their receptor specificity and clinical implications.

3

Identify key contraindications and drug interactions associated with each drug class to ensure safe therapeutic use.

4

Analyze the role of alkylating agents in cancer treatment and understand their mechanism in targeting rapidly dividing cells.

Key Concepts

CONCEPT

DEFINITION

Alpha Blockers

Medications that inhibit alpha-adrenergic receptors, leading to vasodilation. Examples include phentolamine and tamsulosin, which are used in conditions such as hypertension, pheochromocytoma, and benign prostatic hyperplasia (BPH).

Beta Blockers

Drugs that block beta-adrenergic receptors. They are divided into cardioselective (primarily targeting beta-1 receptors) and nonselective types (affecting both beta-1 and beta-2 receptors). They are used in a variety of cardiovascular conditions.

Alkylating Agents

A class of chemotherapy drugs that work by adding alkyl groups to DNA, thereby inhibiting replication and leading to cell death. Key examples include cisplatin, cyclophosphamide, and mechlorethamine, which are used in cancer treatments.

Pharmacokinetics

The study of how drugs are absorbed, distributed, metabolized, and excreted by the body, which influences dosing and frequency of administration.

Drug Interactions

The effects that may occur when two or more drugs interact with each other, potentially altering efficacy and toxicity. Understanding these is essential for safe clinical use.

Example Problems

Example 1

'I'he nurse is assessing an enteral feeding that is infusing via a nasogastric feeding tube. Which statement about this tube is accurate? a It is surgically inserted into the stomach. b It is inserted through the nose into the jejunum. c It is surgically inserted directly into the jejunum. d It is inserted through the nose into the stomach.

Example 2

When administering total parenteral nutrition (TPN), the nurse is aware that one purpose of intravenous fat (lipid) emulsions is to provide which nutrient? a Calories b Amino acids c Minerals d Immunoglobulins

Example 3

The nurse is monitoring a patient who is receiving a total parenteral nutrition (TPN) infusion and notes that the patient has cold clammy skin, shows tachycardia, and is complaining of feeling dizzy. What is the immediate action of the nurse? a Stop the TPN infusion. b Check the patient's blood glucose level. c Order a stat (immediate) electrocardiogram. d Obtain an order for blood cultures.

Example 4

A patient has new orders for administration of peripheral parenteral nutrition (PPN). The nurse knows that PPN is most appropriate in which situation? a Therapy is expected to last longer than 2 weeks. b Therapy is expected to last fewer than 14 days. c A dextrose concentration of $20 \%$ is needed. d Nutritional needs are $3000 \mathrm{kcal} /$ day.

Example 5

During the night shift, a patient's total parenteral nutrition (TPN) infusion runs out, the pharmacy is closed, and a new TPN bag will not be available for about 6 hours. The nurse's most appropriate action at this time would be to a hang a bottle of lipid solution. b hang a bag of normal saline. c hang a bag of $10 \%$ dextrose. d call the prescriber for stat TPN orders.
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Step-by-Step Explanations

QUESTION

How do alpha blockers like phentolamine and tamsulosin work, and what are their primary clinical applications?

STEP-BY-STEP ANSWER:

Step 1: Understand that alpha blockers work by antagonizing alpha-adrenergic receptors, which results in the dilation of blood vessels.
Step 2: Recognize that phentolamine is used in managing hypertensive emergencies and diagnosing pheochromocytoma, while tamsulosin is primarily used for benign prostatic hyperplasia (BPH) by relaxing smooth muscles in the urinary tract.
Step 3: Identify the importance of dosing and monitoring potential side effects such as hypotension.
Final Answer: Alpha blockers function by blocking alpha receptors to promote vasodilation, and they are used in treating conditions like hypertension, pheochromocytoma, and BPH.

Alpha Blockers

QUESTION

What is the difference between cardioselective and nonselective beta blockers, and how does this affect their clinical use?

STEP-BY-STEP ANSWER:

Step 1: Define cardioselective beta blockers as those primarily targeting beta-1 receptors in the heart, reducing heart rate and contractility.
Step 2: Define nonselective beta blockers as those affecting both beta-1 and beta-2 receptors, which may lead to additional side effects such as bronchoconstriction.
Step 3: Discuss clinical implications, noting that cardioselective agents are often preferred in patients with respiratory issues, while nonselective agents might be suitable for other scenarios.
Final Answer: The key difference lies in receptor specificity—cardioselective beta blockers mainly target the heart, making them safer for patients with pulmonary concerns, while nonselective beta blockers act on multiple receptors, potentially causing broader systemic effects.

Beta Blockers

QUESTION

How do alkylating agents like cisplatin, cyclophosphamide, and mechlorethamine function in cancer treatment, and what are key considerations related to their use?

STEP-BY-STEP ANSWER:

Step 1: Understand that alkylating agents work by adding alkyl groups to DNA, thus interfering with DNA replication and leading to cell death in rapidly dividing cells.
Step 2: Identify common alkylating agents such as cisplatin, cyclophosphamide, and mechlorethamine, and their role in treating various cancers.
Step 3: Consider clinical aspects such as dosing, side effects (e.g., myelosuppression, nephrotoxicity), and the need for monitoring patient response and toxicity.
Final Answer: Alkylating agents damage the DNA of cancer cells by adding alkyl groups, effectively inhibiting cell division. They require careful use due to significant side effects and require thorough patient monitoring.

Alkylating Agents

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Common Mistakes

  • Confusing the roles and mechanisms of alpha blockers and beta blockers.
  • Overlooking the different receptor specificities between cardioselective and nonselective beta blockers, leading to inappropriate drug choice.
  • Neglecting to consider potential drug interactions and contraindications, which can increase the risk of adverse reactions.
  • Assuming all alkylating agents have similar toxicity profiles without accounting for individual drug properties and patient-specific factors.