Nursing Pharmacology Chapter 1

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Questions and Answers

What is the primary use of digoxin derived from the foxglove plant?

Respiratory enhancement

Pain relief

Heart rate regulation (correct)

Anxiety reduction

Which of the following is an example of a drug derived from animal sources?

Caffeine

Zinc Sulfate

Aspirin

Heparin (correct)

Which type of drug name is always written in lowercase?

Brand name

Chemical name

Generic name (correct)

Trade name

What is the primary goal of drug therapy in nursing?

Maximize therapeutic effects and minimize adverse reactions (A) Signup and view all the answers

Which of the following statements is true regarding drug administration according to nursing guidelines?

Five rights of administration must be followed (D) Signup and view all the answers

Synthetic drug sources typically refer to:

Laboratory derived products (A) Signup and view all the answers

What is the correct chemical name for the trade name Benadryl?

2(Diphenylmethoxy)-N,N-dimethylethylamine hydrochloride (B) Signup and view all the answers

Which of the following is NOT a property of an ideal drug?

Possession of a complex trade name (C) Signup and view all the answers

What does pharmacokinetics study?

The study of drug absorption, distribution, metabolism, and excretion (A) Signup and view all the answers

What is the main objective of Phase 1 clinical trials?

To find out if the new drug is safe (B) Signup and view all the answers

Which factor does NOT contribute to individual variation in drug response?

Personality type (C) Signup and view all the answers

What does pharmacodynamics involve?

The relationship between drug action and effect (B) Signup and view all the answers

Which of the following types of drug reactions is NOT classified under adverse reactions?

Non-specific reactions (A) Signup and view all the answers

In the development of new drugs, what is the purpose of preclinical trials?

To conduct preliminary research with animals or human cells (D) Signup and view all the answers

What aspect does NOT enhance compliance in drug administration?

Complicated administration routes (A) Signup and view all the answers

What does ADME stand for in pharmacokinetics?

Absorption, Distribution, Metabolism, Elimination (C) Signup and view all the answers

Which of the following routes of administration typically offers 100% bioavailability?

Intravenous (IV) (D) Signup and view all the answers

What is the primary disadvantage of oral drug administration?

First-pass metabolism affecting drug potency (B) Signup and view all the answers

Which mechanism of drug absorption does not require energy and involves movement from a high concentration to a low concentration?

Passive diffusion (C) Signup and view all the answers

Which factor does NOT influence the oral bioavailability of a drug?

Rate of administration (C) Signup and view all the answers

Which route of administration is particularly advantageous for rapidly acting drugs with potential instability in the gastrointestinal tract?

Sublingual (D) Signup and view all the answers

For which purpose is intrathecal/intraventricular drug administration primarily used?

To avoid the blood-brain barrier (C) Signup and view all the answers

What is the main purpose of using depot preparations in intramuscular injections?

Sustained release of medication (A) Signup and view all the answers

Which of the following mechanisms requires energy to transport drug molecules?

Active transport (B) Signup and view all the answers

Which drug is most likely to experience significant first-pass metabolism if taken orally?

Oral propranolol (D) Signup and view all the answers

What is the role of the liver in drug elimination?

It metabolizes drugs and excretes them into bile. (C) Signup and view all the answers

How does grapefruit juice interact with drug metabolism?

Acts as a P450 inhibitor, increasing drug levels. (A) Signup and view all the answers

What processes are involved in the elimination of drugs into urine?

Filtration, proximal tubular secretion, and distal tubular reabsorption. (A) Signup and view all the answers

What effect does alkalinization of urine have on weak acids?

Enhances their renal clearance. (C) Signup and view all the answers

Why might elderly adults experience altered drug absorption?

Increased gastric pH and reduced muscle tone. (C) Signup and view all the answers

What is the significance of drug polarility in renal excretion?

More polar drugs are more efficiently excreted. (A) Signup and view all the answers

Which factor does NOT influence glomerular filtration rate?

Lipid solubility. (A) Signup and view all the answers

Which statement about drug biotransformation is NOT true?

Conjugation reactions require no endogenous substrates. (C) Signup and view all the answers

What is the characteristic of drug absorption in infants?

Greater body surface area increases topical absorption. (A) Signup and view all the answers

How does drug distribution vary between infants and adults?

Infants generally have less protein binding than adults. (D) Signup and view all the answers

Which of the following statements best explains the effect of pH on drug absorption?

The uncharged form of weak acids predominates when the pH is lower than the pKa. (A) Signup and view all the answers

What factor significantly increases the absorption of drugs in the intestines compared to the stomach?

Higher blood flow to the absorption site. (A) Signup and view all the answers

Which of the following roles does P-glycoprotein NOT perform?

Facilitating drug absorption in the intestines. (B) Signup and view all the answers

What is the main consequence of high expression of P-glycoprotein in tissues?

Decreased overall absorption of drugs. (D) Signup and view all the answers

What aspect of drug distribution is most significantly influenced by the rate of blood flow?

Capillary permeability. (D) Signup and view all the answers

Which of the following statements regarding volume of distribution (Vd) is accurate?

Vd can help in calculating the loading dose of a drug. (C) Signup and view all the answers

In what scenario would a drug most likely exhibit zero-order kinetics?

When the drug reaches a saturation point in metabolism. (A) Signup and view all the answers

How does phase I metabolism primarily modify lipophilic drugs?

By oxidizing or reducing the compounds to increase their solubility. (B) Signup and view all the answers

What defines clearance (CL) as it pertains to drug elimination?

The amount of drug eliminated from the body per unit time. (A) Signup and view all the answers

Which of the following factors does NOT affect drug metabolism and excretion?

Concentration of plasma proteins. (C) Signup and view all the answers

Study Notes

Sources of Drugs

Plant Products: Examples include Digoxin from Foxglove, Opium from Poppy, Atropine from Belladonna, Caffeine from Coffee, and Nicotine from Tobacco.
Animal Products: Includes hormones like Premarin (conjugated Oestrogen), Insulin from pigs and cows, and Heparin from pigs and cows.
Inorganic Compounds: Examples are Sodium Chloride, Zinc Sulfate, and Aluminium Hydroxide.
Synthetic Sources: Genetically engineered products like Human Insulin (recombinant).

Drug Names

Chemical Name: Long and complex, e.g., N-acetyl-para-aminophenol.
Generic Name: Single lower-case name, less simple than the trade name, e.g., Paracetamol.
Trade Name: Marketing name in upper case confirmed by the FDA, e.g., Tylenol.

Nursing Role in Pharmacology

Anticipate patient responses to medications.
Administer the correct drug by the right route, at the right time and dosage.
Manage adverse drug effects and toxicities.
Collect baseline data and identify high-risk patients.

Properties of an Ideal Drug

Effectiveness: Must elicit the intended response.
Safety: Should have minimal side effects and not cause addiction.
Selectivity: Targets specific receptors with no adverse effects.
Ease of Administration: Should require fewer doses and be straightforward to use.
Cost-Effectiveness: Affordable, particularly for chronic conditions.
Chemical Stability: Should remain effective during storage.
Simple Generic Name: Easily remembered and pronounced.

Individual Variation Factors

Variation in drug response due to age, gender, weight, liver and kidney function, and genetic variables.

Key Pharmacological Concepts

Pharmacokinetics (ADME): Involves the study of the absorption, distribution, metabolism, and excretion of drugs.
Pharmacodynamics: Focuses on the drug's mechanism of action and its effects on the body.
Toxicology: Examines the adverse effects and toxicity of drugs.

Drug Development Process

Preclinical Trials: Initial testing in vitro or on animals to assess safety and efficacy.
Phase I Trials: Small group of healthy subjects to evaluate safety.
Phase II Trials: Testing for effectiveness on patients with the target condition.
Phase III Trials: Large-scale studies to gather more data on safety and efficacy across diverse populations.

Pharmacokinetics (ADME) Details

Absorption: The process allowing drugs to enter the bloodstream.
Distribution: The transfer of the drug from blood to interstitial and cellular spaces.
Metabolism: Transformation of the drug into metabolites, primarily in the liver.
Elimination: Removal of the drug and its metabolites from the body, mainly via urine.

Routes of Drug Administration

Oral: Convenient but can face first-pass metabolism and absorption issues.
Sublingual: Rapid absorption avoiding first-pass metabolism.
Intravenous (IV): Immediate drug effect but higher infection risk.
Intramuscular (IM) & Subcutaneous (SC): Varying absorption rates based on formulation.
Inhalation: Quick entry into circulation via mucous membranes.
Topical & Transdermal: Local effects and sustained release.

Factors Influencing Absorption

pH and pKa: Uncharged drugs permeate membranes more easily; absorption depends on the drug's chemical properties.
Blood Flow: Increased blood flow enhances absorption efficiency.
Surface Area and Contact Time: More extensive absorptive surfaces (like intestines) increase the likelihood of drug uptake.

Distribution of Drugs

Depends on factors like cardiac output, tissue volume, and protein binding in plasma and tissues.
Volume of Distribution (Vd): Reflects how widely a drug disperses in body fluids. Higher Vd indicates more distribution in tissues.

Drug Elimination Dynamics

Half-Life (t1/2): Time taken for plasma drug concentration to reduce by half; influences frequency and dosing.
Clearance (CL): The speed at which drugs are eliminated from the body, can differ based on Vd.

Enzymatic Drug Metabolism

Metabolism often occurs in two phases: Phase I (modifications like oxidation) and Phase II (conjugation). Phase I can involve cytochrome P450 enzymes.
Potential for first-order (dependence on concentration) or zero-order kinetics (fixed rate regardless of concentration).

Adverse Reactions

Can be predictable (common) or unpredictable (rare), including iatrogenic, carcinogenic, or teratogenic effects.### Drug Biotransformation
Drug metabolism varies genetically among individuals, affecting biotransformation pathways.
Inducers increase metabolism, lowering plasma concentrations and therapeutic effects if the metabolite is inactive.
Inhibitors, particularly P450 inhibitors (e.g., grapefruit juice with CYP 3A4), can elevate drug levels, leading to enhanced therapeutic or toxic effects.

Conjugation Reactions

Lipophilic Phase I metabolites undergo conjugation with endogenous substrates for easier excretion.
Common substrates for conjugation include glucuronic acid, sulfuric acid, acetic acid, and amino acids.

Drug Excretion

Kidney plays a crucial role in drug elimination, requiring drugs to be sufficiently polar.
Three key processes of urinary drug elimination: glomerular filtration, proximal tubular secretion, and distal tubular reabsorption.
Glomerular filtration rate averages 125 mL/min; lipid solubility and pH do not impact this rate.

Renal Excretion Mechanisms

Anionic and cationic transport systems in renal tubules actively secrete drugs.
Drug concentrations in nephric lumen can lead to diffusion back into circulation unless modified to increase polarity through liver metabolism.

Ion Trapping

Weak acid excretion is enhanced by urine alkalinization (e.g., bicarbonate for phenobarbital overdose).
Weak base excretion increases with urine acidification (e.g., NH4Cl for amphetamine overdose).

Routes of Drug Loss

Elimination occurs through various means: liver metabolism, feces, lungs, and breast milk.
Liver contributes to drug loss via metabolism or excretion into bile; renal failure patients may benefit from liver-excreted drugs.

Differences in Drug Metabolism Across Age Groups

Infant metabolism: Immature gastric cells lead to higher gastric pH, affecting absorption; limited first-pass elimination due to low liver enzyme levels; greater total body water but less fat and protein binding.
Elderly metabolism: Reduced gastric pH, slower GI transit, decreased liver enzyme production affects drug clearance and necessitates dosage adjustments.

Pharmacology Concepts

Pharmacodynamics focuses on drugs' biological effects and mechanisms of action.
Drug actions: physical (adsorption) or chemical (neutralization); interactions with enzymes can be reversible or irreversible.
Factors affecting drug action include age, body weight, gender, routes of administration, drug tolerance and hypersensitivity, and pharmacogenetics.

Drug Toxicity and Dosage

Types of drug toxicity: predictable (type A) and unpredictable (type B) based on genetic predispositions.
Terminology includes therapeutic dose, maximum tolerated dose, lethal dose, loading dose, and maintenance dose.
Drug interactions can lead to augmented pharmacological effects or unexpected reactions, particularly in sensitive populations.

Summary of Key Pharmacokinetic Principles

Ideal pharmacology encompasses understanding drug formulation, actions, and effects in biological systems.
Bioavailability defines the proportion of the drug reaching systemic circulation intact.
Sublingual administration avoids first-pass metabolism and can provide rapid effects.

Questions for Review

What factors modify the pharmacokinetics of drugs in different age groups?
How do routes of administration influence drug efficacy?
What is the significance of drug receptors and mechanisms of action in pharmacodynamics?

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Description

Explore the fundamentals of nursing pharmacology in this introductory quiz. Focus on the sources of drugs, including plant products and their medical uses. Test your knowledge on essential pharmacological concepts and their applications in nursing.